The Nextion Instruction Set

These are the set of commands that Nextion can use.
They are categorized into only a few categories

  1. General Rules and Practices … <goto>
  2. Assignment Statements … <goto>
  3. Operational Commands … <goto>
  4. GUI Designing Commands … <goto>
  5. Color Code Constants … <goto>
  6. System Variables … <goto>
  7. Format of Nextion Return Data … <goto>

Legend:

: Basic : Discovery : Enhanced : Intelligent : All
: Basic, Discovery or Enhanced : Basic or Enhanced : Enhanced or Intelligent

1 – General Rules and Practices

No.General Rule or Practice
1 All instructions over serial: are terminated with three bytes of 0xFF 0xFF 0xFF
ie: decimal: 255 or hex: 0xFF or ansichar: ÿ or binary: 11111111
ie byte ndt[3] = {255,255,255}; write(ndt,3); or print(“\xFF\xFF\xFF”); or print(“ÿÿÿ”)
2 All instructions and parameters are in ASCII
3 All instructions are in lowercase letters
4 Blocks of code and enclosed within braces { } can not be sent over serial
this means if, for, and while commands can not be used over serial
5 A space char 0x20 is used to separate command from parameters.
6 There are no spaces in parameters unless specifically stated
7 Nextion uses integer math and does not have real or floating support.
8 Assignment are non-complex evaluating fully when reaching value after operator.
9 Comparison evaluation is non-complex, but can be joined (see && and ||).
10 Instructions over serial are processed on receiving termination (see 1.1)
11 Character escaping is performed using two text chars: \r creates 2 bytes 0x0D 0x0A, \” 0x22 and \\ for 0x5C
12 Nextion does not support order of operations. sys0=3+(8*4) is invalid.
13 16-bit 565 Colors are in decimal from 0 to 65535 (see 5.Note)
14 Text values must be encapsulated with double quotes: ie “Hello”
15 Items which are specific to Enhanced Models are noted with
16Transparent Data Mode (used by addt and wept commands)

  1. MCU sending to Nextion
    1. MCU sends command. ie: wept 30,20ÿÿÿ or addt 1,0,320ÿÿÿ
    2. Nextion requires ~5ms to prepare for transparent mode data transfer
    3. Nextion sends “Ready” 0xFE 0xFF 0xFF 0xFF Return Data (see 7.32)
    4. MCU can now send specified quantity (20) of raw bytes to Nextion
    5. Nextion receives raw bytes from MCU until specified quantity (20) is received
    6. Nextion sends “Finished” 0xFD 0xFF 0xFF 0xFF Return Data (see 7.31)
    7. MCU and Nextion can proceed to next command

Note: Nextion will remain waiting at step 5 until every byte of specified quantity is received.
– During this time Nextion can not execute any other commands, and may indeed hang if the MCU fails to deliver the number of bytes as specified by the command parameter.
– data quantity limited by serial buffer (all commands+terminations + data < 1024)

17 Only component attributes in green and non readonly system variables can be assigned new values at runtime. All others are readonly at runtime with the exception of .objname
18 Numeric values can now be entered with byte-aligned hex. ie: n0.val=0x01FF
19 Advanced. Address mode is an advanced technique prepending the serial instruction with two bytes for the address. Two byte address is to be sent in little endian order, ie: 2556 is sent 0xFC 0x09. By default, the Nextion address is 0 and does not require two byte prefixing. When the two byte addressing is used, Nextion will only respond to the command if its address matches the two byte prefix, or the transmitted address is 65535 broadcast. See the addr system variable.
20 Advanced. Protocol Reparse mode is an advanced technique that allows users to define their own incoming protocol and incoming serial data handling. When in active Protocol Reparse mode, incoming serial data will not be processed natively by the Nextion firmware but will wait in the serial buffer for processing. To exit active Protocol Reparse mode, recmod must be set back to passive (ie: in Nextion logic as recmod=0), which can not be achieved via serial. Send DRAKJHSUYDGBNCJHGJKSHBDNÿÿÿ via serial to exit active mode serially. Most HMI applications will not require Protocol Reparse mode and should be skipped if not fully understood.
21 Commenting user code inside Events uses the double-slash (two characters of forward slash / ) technique. See 2.30 for proper usage.

2 – Assignment Statements

No.Data TypeOperatorDescription/Example (see 1.8 and 1.17)
1Text= Assignment. Right side will be evaluated with result placed in left side. Component .txt-maxl needs to be large enough to hold result.
t0.txt=”Hello”
2Text+= Text Addition. Will concatenate left side with right side with result placed left side. ie t0.txt+=”Hello” is equivalent to t0.txt=t0.txt+”Hello”.
t0.txt=”-“+t0.txt becomes t0.txt=t0.txt+”-“.
Use temp variable to prepend. va0.txt=t0.txt t0.txt=”-“+va0.txt
t0.txt+=” World” // append ” World” to t0.txt
//When contents of t0.txt is “Hello” becomes “Hello World”
3Text-= Text Subtraction. Will remove right side (a specified numeric amount of characters to remove) from end of left side and result placed in left side.
t0.txt-=4 or t0.txt=t0.txt-4 // remove last 4 chars from t0.txt
4Text\ Escape Character. (see 1.11)
Supported is \r hex 0x0D 0x0A, \” hex 0x22, \\ hex 0x5C,
t0.txt=”\r”
5Text== Boolean Equality. Evaluate left side to right side.
If both left and right sides are the same creates a true condition
if(t0.txt==va0.txt)
6Text!= Boolean Inequality. Evaluate left side to right side.
If both left and right sides are different creates a true condition
if(t0.txt!=va0.txt)
7Numeric= Assignment. Right side of equation will be evaluated and result placed in left side. If more than one operator on right side, full evaluation and assignment will occur at each operator.
n0.val=bauds // places bauds value in n0.val component
8Numeric+= Numeric Addition. Adds value of left side and right side with result placed in left side. n0.val+=4 is equivalent to n0.val=n0.val+4
n0.val+=va0.val
9Numeric-= Numeric Subtraction. Subtracts right side from left side with result placed in left side. n0.val-=4 is equivalent to n0.val=n0.val-4
n0.val-=60 // decreases value of n0.val by 60
10Numeric*= Numeric Multiplication. Multiplies left side with right side with product result placed in left side. n0.val*=2 is equivalent of n0.val=n0.val*2
n0.val*=2
11Numeric/= Numeric Division. Equates division of numerator (left side) and divisor (right side) and places integer quotient in left side. 60000/20001=2
n0.val/=60
12Numeric%= Numeric Modulo. Equates division of numerator (left side) and divisor (right side) and places integer remainder in left side. Divisor MUST be a constant. 60000/20001=19998
n0.val%=60
13Numeric<< Arithmetic Bit Shift Left. Moves all bits specified number to the left.
Using the 16-bit example that follows, (32-bit uses similar rules)
All bits shifted above 15 are lost and undefined bits become 0
n0.val=n0.val<<4
0 0 0 0.0 0 1 1.1 1 0 0.0 0 0 1
0 0 1 1.1 1 0 0.0 0 0 1.
0 0 1 1.1 1 0 0.0 0 0 1.0 0 0 0
14Numeric>> Arithmetic Bit Shift Right. Moves all bits specified number to the right.
Using the 16-bit example that follows, (32-bit uses similar rules)
All bits shifted below 0 are lost and undefined bits become the signed bit.
When signed bit is 1 (value is negative) then left filled is with 1’s
When signed bit is 0 (value is positive) then left filled is with 0’s
n0.val=n0.val>>4
0 0 0 0.0 0 1 1.1 1 0 0.0 0 0 1
0 0 0 0.0 0 1 1.1 1 0 0
0 0 0 0.0 0 0 0.0 0 1 1.1 1 0 0
15Numeric& Logical Bitwise AND. Compares all bits left side to all bits right side(mask)
Using the 16-bit example that follows, (32-bit uses similar rules)
Result is a bit of 1 where both left and right bits were 1
n0.val=n0.val&35381
0 1 0 1.1 0 1 1.0 0 1 0.0 1 0 1 n0.val of 23333
1 0 0 0.1 0 1 0.0 0 1 1.0 1 0 1 mask of 35381
0 0 0 0.1 0 1 0.0 0 1 0.0 1 0 1 result is 2597
16Numeric| Logical Bitwise OR. Compares all bits left side to all bits right side
Using the 16-bit example that follows, (32-bit uses similar rules)
Result is a bit of 1 where either left or right bits were 1
n0.val=n0.val|35381
0 1 0 1.1 0 1 1.0 0 1 0.0 1 0 1 n0.val of 23333
1 0 0 0.1 0 1 0.0 0 1 1.0 1 0 1 constant 35381
1 1 0 1.1 0 1 1.0 0 1 1.0 1 0 1 result is 56117
17Numeric^ Logical Bitwise XOR. Applies bit inversion to all bits in the bitmask
Using the 16-bit example that follows, (32-bit uses similar rules)
Result is a bit inverted where maskbit was 1, unchanged where maskbit was 0
n0.val=n0.val^35381
0 1 0 1.1 0 1 1.0 0 1 0.0 1 0 1 n0.val of 23333
1 0 0 0.1 0 1 0.0 0 1 1.0 1 0 1 bitmask of 35381
1 1 0 1.0 0 0 1.0 0 0 1.0 0 0 0 result is 53520
18Numeric== Boolean Equality. Evaluate left side to right side.
If both left and right sides are the same creates a true condition
if(n0.val==va0.val)
19Numeric!= Boolean Inequality. Evaluate left side to right side.
If both left and right sides are different creates a true condition
if(n0.val!=va0.val)
20Numeric< Boolean Less than. Evaluate left side to right side.
If left side is less than right side creates a true condition
while(n0.val<va0.val)
21Numeric<= Boolean Less than or Equal. Evaluate left side to right side.
If left side is less than or equal to right side creates a true condition
while(n0.val<=va0.val)
22Numeric> Boolean Greater than. Evaluate left side to right side.
If left side is greater than right side creates a true condition
while(n0.val>va0.val)
23Numeric>= Boolean Greater than or Equal. Evaluate left side to right side.
If left side is greater than or equal to right side creates a true condition
while(n0.val>=va0.val)
24Code{ } Code Block begins with open brace { on line by itself
Code Block ends with closing brace } beginning a new line
see if (see 3.25) while (see 3.26) and for (see 3.27)
25Code&& Condition Joiner AND
Conditions may be joined with no spaces between conditions, left to right evaluation
see if (see 3.25) while (see 3.26) and for (see 3.27)
26Code|| Condition Joiner OR
Conditions may be joined with no spaces between conditions, left to right evaluation
see if (see 3.25) while (see 3.26) and for (see 3.27)
27Code( ) Conditions enclosure begins with open parenthesis (
and ends with closing parenthesis ) at end of line.
Parenthesis are not allowed to create complex statements.
see if (see 3.25) while (see 3.26) and for (see 3.27)
28Code. Period Separator. Separates Page, Component and Attributes
Also used with page index and component array. (see 2.29)
page1.va0.val or p0.pic
29Code[ ] Array[index]. There are 3 arrays. Keyboard source showcases 2 arrays.
The b[.id] component array which takes component .id as index
The p[index] page array which takes page index as index
These (p[].b[]) need to be used with caution and mindful purpose. Reference to a component without specified Attribute can create for long and potentially frustrating debug sessions. The third array is the Serial Buffer Data u[index] array. This is valid when in active Protocol Reparse mode. Protocol Reparse is an advanced technique that should be skipped if not fully understood.
p[pageindex].b[component.id].attribute // global scope
b[component.id].attribute // local scope on current page
30Comment// Double-Slash Commenting to add user comments to code.
Everything to the right of, and including, the double-slash is a comment that will not be executed by the Nextion interpreter. Comments should: 1) occur on a line by themselves with the double-slash at the beginning of the line (no leading spaces), 2) immediately following code on a line without a space separating code and the double slash. Commenting of code blocks should occur: 1) before the condition/iteration 2) inside the opening and closing braces 3) after the code block. Notes: It is important to note that comments can not interrupt code blocks without causing an “Error: Index was outside the bounds of the array”. Comments are counted towards the overall “code + attributes” hard limit of 65534.
// these are valid comments
sys0=0// reset sys0 to zero

The following showcases valid/invalid use

//valid comment before condition/iteration
for(sys0=0;sys0<=sys1;sys0++)
// invalid comment between condition/iteration and block
{
  doevents//valid comment after code on same line
  // valid comment inside block
}
// valid comment outside block

3 – Operational Commands

No.NameParam CountDescription and Usage/Parameters/Examples
1page1 Change page to page specified. Unloads old page to load specified page.
Nextion loads page 0 by default on power on.
usage: page <pid>
<pid> is either the page index number, or pagename
page 0 // Change page to indexed page 0
page main // Change page to the page named main
2ref1 Refresh component (auto-refresh when attribute changes since v0.38)
– if component is obstructed (stacking), ref brings component to top.
usage: ref <cid>
<cid> is component’s .id or .objname attribute of component to refresh
– when <cid> is 0 (page component) refreshes all on the current page.
ref t0 // Refreshes the component with .objname of t0
ref 3 // Refreshes the component with .id of 3
ref 0 // Refreshes all components on the current page (same as ref 255)
3click2 Trigger the specified components Touch Press/Release Event
As event code is always local, object can not be page prefixed
usage: click <cid>,<event>
<cid> is component’s .id or .objname attribute of component to refresh
<event> is 1 to trigger Press Event, 0 to trigger Release Events
click b0,1 // Trigger Touch Press Event of component with .objname b0
click 4,0 // Trigger Touch Release Event of component with .id 4
4ref_stop0 Stops default waveform refreshing (will not refresh when data point added)
– waveform refreshing will resume with ref_star (see 3.5)
usage: ref_stop
ref_stop // stop refreshing the waveform on each data point added
5ref_star0 Resume default waveform refreshing (refresh on data point add)
– used to resume waveform refreshing stopped by ref_stop (see 3.4)
usage: ref_start
ref_star // resume default refreshing, refresh on each data point added
6get1 Send attribute/constant over serial (0x70/0x71 Return Data)
usage: get <attribute>
<attribute> is either numeric value, .txt contents, or constant
get t0.txt // sends text contents of t0.txt in 0x70 Return Data format
get “123” // sends text constant “123” in 0x70 Return Data format
get n0.val // sends numeric value of n0.val in 0x71 Return Data format
get 123 // sends numeric constant 123 in 0x71 Return Data format
7sendme0 Sends number of currently loaded page over serial (0x66 Return Data)
– number of currently loaded page is stored in system variable dp
– used in a page’s initialize event will auto-send as page loads
usage: sendme
sendme // sends the value of dp in 0x66 Return Data Format
8covx4 Convert variable from numeric type to text, or text to numeric type
– text must be text ASCII representation of an integer value.
– source and destination types must not be of the same type
– when numeric source and hex format chosen, length must be even for bytewise hex digits (0, 2, 4, 6 or 8)
ie: (len 4) positive significant (byte 0 to 3), 123 = 0000007B = 007B
ie: (len 4) negative significant (byte 3 to 0), -123 = FFFFFF85 = FFFF
– value is more than allowed space results in a truncation
– it is recommended to ensure handling source length in user code before covx
– in v0.53, covx is deemed undefined if source is larger than length or
dest txt_maxl is smaller than requested length.
(some of these undefines, can be exploited)
ie: src numeric value of 123 with length 0, result is dest text “123”
– when length is fixed and value is less, leading zeros will be added
ie: src numeric value of 123 with length 4, result is dest text “0123”
– when value is larger than length, .txt truncated to least significant digits
ie: src numeric value of 23425 with length 4 result is dest text “2342”
usage: covx <src>,<dest>,<length>,<format>
<src> is text attribute (or numeric attribute when <dest> is text)
<dest> is numeric attribute (or text attribute when <src> is numeric)
<length> will determine if leading zeros added to conversion to text
<format> 0: integer, 1: Comma separated 1,000s, 2: Hex
covx h0.val,t0.txt,0,0 // convert value of h0 into t0.txt without leading zeros
covx t0.txt,h0.val,0,0 // convert t0.txt into integer in h0.val <length> ignored.
covx h0.val,t0.txt,4,0 // convert value of h0 into t0.txt with exactly 4 digits
covx h0.val,t0.txt,4,1 // convert value of h0 into t0.txt with commas
covx h0.val,t0.txt,4,2 // convert value of h0 into t0.txt in 4 hex digits (2 Bytes)
Invalid: covx h0.val,va0.val,0,0 or covx t0.txt,va0.txt,0,0 // src & dest same type.
8acov3 Depreciated. Convert from numeric type to text, or text to numeric type
– text must be text ASCII representation of an integer value.
– source and destination types must not be of the same type
– when length is fixed and value is less, leading zeros will be added
ie: src numeric value of 123 with length 4, result is dest text “0123”
– dest txt_maxl and length needs be large enough to accommodate conversion.
ie: src numeric value of 123 with length 0, result is dest text “123”
– when value is larger than length, .txt results in a truncation
– it is recommended to handle source length in user code before cov
Note:v0.53 changed behaviour from previous pre/post v0.53 behaviours.
cov is deemed undefined if source is larger than length or the dest txt_maxl is
smaller than the requested length. Some undefines are exploitable.
usage: cov <src>,<dest>,<length>
<src> is text attribute (or numeric attribute when <dest> is text)
<dest> is numeric attribute (or text attribute when <src> is numeric)
<length> will determine if leading zeros added to conversion to text
cov h0.val,t0.txt,0 // convert value of h0 into t0.txt without leading zeros
cov t0.txt,h0.val,0 // convert integer into t0.txt from h0.val <length> ignored.
cov h0.val,t0.txt,4 // convert value of h0 into t0.txt with exactly 4 digits
Invalid: cov h0.val,va0.val,0 or cov t0.txt,va0.txt,0 // src & dest same type.
9touch_j0 Recalibrate the Resistive Nextion device’s touch sensor
– presents 4 points on screen for user to touch, saves, and then reboots.
– typically not required as device is calibrated at factory
– sensor can be effected by changes of conditions in environment
– Capacitive Nextion devices can not be user calibrated.
usage: touch_j
touch_j // trigger the recalibration of touch sensor
10substr4 Extract character or characters from contents of a Text attribute
usage: substr <src>,<dest>,<start>,<count>
<src> is text attribute where text will be extracted from
<dest> is text attribute to where extracted text will be placed
<start> is start position for extraction (0 is first char, 1 second)
<count> is the number of characters to extract
substr va0.txt,t0.txt,0,5 // extract first 5 chars from va0.txt, put into t0.txt
11vis2 Hide or Show component on current page
– show will refresh component and bring it to the forefront layer
– hide will remove component visually, touch events will be disabled
– use layering with mindful purpose, can cause ripping and flickering.
– use with caution and mindful purpose, may lead to difficult debug session
usage: vis <comp><state>
<comp> is either .objname or .id of component on current page,
– valid .id is 0 – page, 1 to 250 if component exists, and 255 for all
<state> is either 0 to hide, or 1 to show.
vis b0,0 // hide component with .objname b0
vis b0,1 // show component with .objname b0, refresh on front layer
vis 1,0 // hide component with .id 1
vis 1,1 // show component with .id 1, refresh on front layer
vis 255,0 // hides all components on the current page
12tsw2 Enable or disable touch events for component on current page
– by default, all components are enabled unless disabled by tsw
– use with caution and mindful purpose, may lead to difficult debug session
usage: tsw <comp><state>
<comp> is either .objname or .id of component on current page,
– valid .id is 0 – page, 1 to 250 if component exists, and 255 for all
<state> is either 0 to disable, or 1 to enable.
tsw b0,0 // disable Touch Press/Release events for component b0
tsw b0,1 // enable Touch Press/Release events for component b0
tsw 1,0 // disable Touch Press/Release events for component with id 1
tsw 1,1 // enable Touch Press/Release events for component with id 1
tsw 255,0 // disable all Touch Press/Release events on current page
13com_stop0 Stop execution of instructions received from Serial
– Serial will continue to receive and store in buffer.
– execution of instructions from Serial will resume with com_star (see 3.14)
– using com_stop and com_star may cause a buffer overflow condition.
– Refer to device datasheet for buffer size and command queue size
usage: com_stop
com_stop // stops execution of instructions from Serial
14com_star0 Resume execution of instructions received from Serial
– used to resume an execution stop caused by com_stop (see 3.13)
– when com_star received, all instructions in buffer will be executed
– using com_stop and com_star may cause a buffer overflow condition.
– Refer to device datasheet for buffer size and command queue size
usage: com_star
com_star // resume execution of instruction from Serial
15randset2 Set the Random Generator Range for use with rand (see 6.14)
– range will persist until changed or Nextion rebooted
– set range to desired range before using rand
– power on default range is -2147483648 to 2147483647, runtime range is user definable.
usage: randset <min>,<max>
<min> is value is -2147483648 to 2147483647
<max> is value greater than min and less than 2147483647
randset 1,100 //set current random generator range from 1 to 100
randset 0,65535 //set current random generator range from 0 to 65535
16code_c0 Clear the commands/data queued in command buffer without execution
usage: code_c
code_c // Clears the command buffer without execution
17prints2 Send raw formatted data over Serial to MCU
– prints does not use Nextion Return Data, user must handle MCU side
– qty of data may be limited by serial buffer (all data < 1024)
– numeric value sent in 4 byte 32-bit little endian order
value = byte1+byte2*256+byte3*65536+byte4*16777216
– text content sent is sent 1 ASCII byte per character, without null byte.
usage: prints <attr>,<length>
<attr> is either component attribute, variable or Constant
<length> is either 0 (all) or number to limit the bytes to send.
prints t0.txt,0 // return 1 byte per char of t0.txt without null byte ending.
prints t0.txt,4 // returns first 4 bytes, 1 byte per char of t0.txt without null byte ending.
prints j0.val,0 // return 4 bytes for j0.val in little endian order
prints j0.val,1 // returns 1 byte of j0.val in little endian order
prints “123”,2 // return 2 bytes for text “12” 0x31 0x32
prints 123,2 // returns 2 bytes for value 123 0x7B 0x00
17aprint1 Depreciated. Send raw formatted data over Serial to MCU
– print/printh does not use Nextion Return Data, user must handle MCU side
– qty of data may be limited by serial buffer (all data < 1024)
– numeric value sent in 4 byte 32-bit little endian order
value = byte1+byte2*256+byte3*65536+byte4*16777216
– text content sent is sent 1 ASCII byte per character, without null byte.
usage: print <attr>
<attr> is either component attribute, variable or Constant
print t0.txt // return 1 byte per char of t0.txt without null byte ending.
print j0.val // return 4 bytes for j0.val in little endian order
print “123” // return 3 bytes for text “123” 0x31 0x32 0x33
print 123 // return 4 bytes for value 123 0x7B 0x00 0x00 0x00
18printh1 to
many
Send raw byte or multiple raw bytes over Serial to MCU
– printh is one of the few commands that parameter uses space char 0x20
– when more than one byte is being sent a space separates each byte
– byte is represented by 2 of (ASCII char of hexadecimal value per nibble)
– qty may be limited by serial buffer (all data < 1024)
– print/printh does not use Nextion Return Data, user must handle MCU side
usage: printh <hexhex>[<space><hexhex][…<space><hexhex]
<hexhex> is hexadecimal value of each nibble. 0x34 as 34
<space> is a space char 0x20, used to separate each <hexhex> pair
printh 0d // send single byte: value 13 hex: 0x0d
printh 0d 0a // send two bytes: value 13,10 hex: 0x0d0x0a
19add3 Add single value to Waveform Channel
– waveform channel data range is min 0, max 255
– 1 pixel column is used per data value added
– y placement is if value < s0.h then s0.y+s0.h-value, otherwise s0.y
usage: add <waveform>,<channel>,<value>
<waveform> is the .id of the waveform component
<channel> is the channel the data will be added to
<value> is ASCII text of data value, or numeric value
– valid: va0.val or sys0 or j0.val or 10
add 1,0,30 // add value 30 to Channel 0 of Waveform with .id 1
add 2,1,h0.val // add h0.val to Channel 1 of Waveform with .id 2
20addt3 Add specified number of bytes to Waveform Channel over Serial from MCU
– waveform channel data range is min 0, max 255
– 1 pixel column is used per data value added.
– addt uses Transparent Data Mode (see 1.16)
– waveform will not refresh until Transparent Data Mode completes.
– qty limited by serial buffer (all commands+terminations + data < 1024)
– also refer to add command (see 3.19)
usage: add <waveform>,<channel>,<qty>
<waveform> is the .id of the waveform component
<channel> is the channel the data will be added to
<qty> is the number of byte values to add to <channel>
addt 2,0,20 // adds 20 bytes to Channel 0 Waveform with .id 2 from serial
// byte of data is not ASCII text of byte value, but raw byte of data.
21cle3 Clear waveform channel data
usage: cle <waveform>,<channel>
<waveform> is the .id of the waveform component
<channel> is the channel to clear
<channel> must be a valid channel: < waveform.ch or 255
0 if .ch 1, 1 if .ch 2, 2 if .ch 3, 3 if .ch=4 and 255 (all channels)
cle 1,0 // clear channel 0 data from waveform with .id 1
cle 2,255 // clear all channels from waveform with .id 2
22rest0 Resets the Nextion Device
usage: rest
rest // immediate reset of Nextion device – reboot.
23doevents0 Force immediate screen refresh and receive serial bytes to buffer
– useful inside exclusive code block for visual refresh (see 3.26 and 3.27)
usage: doevents
doevents // allows refresh and serial to receive during code block
24strlen2 Computes the length of string in <txt> and puts value in <len>
usage: strlen <txt>,<len>
<txt> must be a string attribute ie: t0.txt, va0.txt
<len> must be numeric ie: n0.val, sys0, va0.val
strlen t0.txt,n0.val // assigns n0.val with length of t0.txt content
24abtlen2 Computes number of bytes string in <txt> uses and puts value in <len>
usage: btlen <txt>,<len>
<txt> must be a string attribute ie: t0.txt, va0.txt
<len> must be numeric ie: n0.val, sys0, va0.val
btlen t0.txt,n0.val // assigns n0.val with number of bytes t0.txt occupies
25ifBlock Conditionally execute code block if boolean condition is met
– execute commands within block { } if (conditions) is met.
– nested conditions using () is not allowed. invalid: ((h0.val+3)>0)
– block opening brace { must be on line by itself
– no space between block close brace } and else. valid: }else invalid: } else
– Text comparison supports ==, !=
– Numerical comparison supports >, <, ==, !=, >=, <=
– conditions can be joined with && or || with no spaces used
– nested “if” and “else if” supported.
usage: if condition block [else if condition block] [else block]
– (conditions) is a simple non-complex boolean comparison evaluating left to right
valid: (j0.val>75) invalid: (j0.val+1>75) invalid: (j0.val<now.val+60)
if(t0.txt=="123456")
{
  page 1
}

if(t0.txt=="123456"||sys0==14&&n0.val==12)
{
  page 1
}

if(t0.txt=="123456"&&sys0!=14)
{
  page 1
}

if(n0.val==123)
{
  b0.txt="stop"
}else
{
  b0.txt="start"
}

if(rtc==1)
{
  t0.txt="Jan"
}else if(rtc1==2)
{
  t0.txt="Feb"
}else if(rtc1==3)
{
  t0.txt="Mar"
}else
{
  t0.txt="etc"
}
26whileBlock Continually executes code block until boolean condition is no longer met
– tests boolean condition and execute commands within block { } if conditions was met and continues to re-execute block until condition is not met.
– nested conditions using () is not allowed. invalid: ((h0.val+3)>0)
– block opening brace { must be on line by itself
– Text comparison supports ==, !=
– Numerical comparison supports >, <, ==, !=, >=, <=
– conditions can be joined with && or || with no spaces used
– block runs exclusively until completion unless doevents used (see 3.23)
usage: while condition block
– (conditions) is a simple non-complex boolean comparison evaluating left to right
valid: (j0.val>75) invalid: (j0.val+1>75)
// increment n0.val as lon as n0.val < 100.  result: b0.val=100
// will not visually see n0.val increment, refresh when while-loop completes
while(n0.val<100)
{
  n0.val++
}

//increment n0.val as long as n0.val < 100. result: n0.val=100
// will visually see n0.val increment, refresh each evaluation of while-loop
while(n0.val<100)
{
  n0.val++
  doevents
}
27forBlock Iterate execution of code block as long as boolean condition is met
– executes init_assignment, then tests boolean condition and executes
commands within block { } if boolean condition is met, when iteration of
block execution completes step_assignment is executed. Continues to
iterate block and step_assignment until boolean condition is not met.
– nested conditions using () is not allowed. invalid: ((h0.val+3)>0)
– block opening brace { must be on line by itself
– Text comparison supports ==, !=
– Numerical comparison supports >, <, ==, !=, >=, <=
– conditions can be joined with && or || with no spaces used
– block runs exclusively until completion unless doevents used (see 3.23)
usage: for(init_assignment;condition;step_assignment) block
– init_assignment and step_assignment are simple non-complex statement
valid: n0.val=4, sys2++, n0.val=sys2*4+3 invalid: n0.val=3+(sys2*4)-1
– (conditions) is a simple non-complex boolean comparison evaluating left to right
valid: (j0.val>75) invalid: (j0.val+1>75)
// iterate n0.val by 1's as long as n0.val<100. result: n0.val=100
// will not visually see n0val increment until for-loop completes
for(n0.val=0;n0.val<100;n0.val++)
{
}

////iterate n0.val by 2's as long as n0.val<100. result: n0.val=100
// will visually see n0.val increment when doevents processed
for(n0.val=0;n0.val<100;n0.val+=2)
{
  doevents
}
28wepo2 Store value/string to EEPROM
– EEPROM valid address range is from 0 to 1023 (1K EEPROM)
– numeric value length: is 4 bytes, -2147483648 to 2147483647
– numeric data type signed long integer, stored in little endian order.
val[addr+3]*16777216+val[addr+2]*65536+val[addr+1]*256+val[addr] – string content length: .txt content is .txt-maxl +1, or constant length +1
usage: wepo <attr>,<addr>
<attr> is variable or constant
<addr> is storage starting address in EEPROM
wepo t0.txt,10 // writes t0.txt contents in addresses 10 to 10+t0.txt-maxl
wepo “abcd”,10 // write constant “abcd” in addresses 10 to 14
wepo 11,10 // write constant 11 in addresses 10 to 13
wepo n0.val,10 // write value n0.val in addresses 10 to 13
29repo2 Read value from EEPROM
– EEPROM valid address range is from 0 to 1023 (1K EEPROM)
– numeric value length: is 4 bytes, -2147483648 to 2147483647
– numeric data type signed long integer, stored in little endian order.
val[addr+3]*16777216+val[addr+2]*65536+val[addr+1]*256+val[addr] – string content length: .txt content is lesser of .txt-maxl or until null reached.
usage: repo <attr>,<addr>
<attr> is variable or constant
<addr> is storage starting address in EEPROM
repo t0.txt,10 // reads qty .txt-maxl chars (or until null) from 10 into t0.txt
repo n0.val,10 // reads 4 bytes from address 10 to 13 into n0.val
30wept2 Store specified number of bytes to EEPROM over Serial from MCU
– EEPROM valid address range is from 0 to 1023 (1K EEPROM)
– wept uses Transparent Data Mode (see 1.16)
– qty limited by serial buffer (all commands+terminations + data < 1024)
usage: wept <addr>,<qty>
<addr> is storage starting address in EEPROM
<qty> is the number of bytes to store
wept 30,20 // writes 20 bytes into EEPROM addresses 30 to 49 from serial
// byte of data is not ASCII text of byte value, but raw byte of data.
31rept2 Read specified number of bytes from EEPROM over Serial to MCU
– EEPROM valid address range is from 0 to 1023 (1K EEPROM)
usage: rept <addr>,<qty>
<addr> is storage starting address in EEPROM
<qty> is the number of bytes to read
rept 30,20 // sends 20 bytes from EEPROM addresses 30 to 49 to serial
// byte of data is not ASCII text of byte value, but raw byte of data.
32cfgpio3 Configure Nextion GPIO
usage: cfgpio <io><mode><comp>
<io> is the number of the extended I/O pin.
– Valid values in PWM output mode: 4 to 7, all other modes 0 to 7.
<mode> is the working mode of pin selected by <io>.
– Valid values: 0-pull up input, 1-input binding, 2-push pull output,
3-PWM output, 4-open drain output.
<comp> component .objname or .id when <mode> is 1 (otherwise use 0)
– in binding mode, cfgpio needs to be declared after every refresh of page to reconnect to Touch event, best to put cfgpio in page pre-initialization event
cfgpio 0,0,0 // configures io0 as a pull-up input. Read as n0.val=pio0.
cfgpio 1,2,0 // configures io1 as a push-pull output, write as pio1=1
cfgpio 2,1, b0 // configures io2 as binding input with current page b0.
// binding triggers b0 Press on falling edge and b0 Release on rising edge
For PWM mode, set duty cycle before cfgpio: ie: pwm4=20 for 20% duty.
cfgpio 4,3,0 // configures io4 as PWM output. pwmf=933 to change Hz.
// changing pwmf changes frequency of all configured PWM io4 to io7
33ucopy4 Advanced. Read Only. Valid in active Protocol Reparse mode.
Copies data from the serial buffer.
When Nextion is in active Protocol Reparse mode, ucopy copies data from the serial buffer. Most HMI applications will not require Protocol Reparse and should be skipped if not fully understood.
usage: ucopy <attr>,<srcstart>,<len>,<deststart>
<attr> must be a writeable attribute ie: t0.txt, va0.val
<srcstart> must be numeric value ie: 0
<len> must be a numeric value ie: 4
<deststart> must be numeric value ie: 0
ucopy n0.val,0,2,0 // copy buffer bytes 0,1 to lower 2 bytes of n0.val
ucopy n0.val,0,2,2 // copy buffer bytes 0,1 to upper 2 bytes of n0.val
ucopy n0.val,0,4,0 // copy buffer bytes 0,1,2,3 to n0.val
ucopy t0.txt,0,10,0 // copy buffer bytes 0 to 9 into t0.txt
34move7 Move component.
usage: move <comp>,<x1>,<y1>,<x2>,<y2>,<priority>,<time>
<comp> is the component name or component id
<x1> is the starting X coordinate
<y1> is the starting Y coordinate
<x2> is the destination X coordinate
<y2> is the destination Y coordinate
<priority> is a value 0 to 100, 100 being highest priority
<time> is time in ms.
move t0,-30,-30,100,150,95,120 // 120ms to move t0 into position 100,150
move t1,-30,-30,200,150,90,180 // 180ms to move t1 into position 200,150
move t2,-30,-30,300,150,100,150 // 150ms to move t2 into position 300,150
// given the example priorities, t2 moves first, then t0 and lastly t1
35play3 Play audio resource on selected Channel
usage: play <ch>,<resource>,<loop>
<ch> is the channel 0 or 1
<resource> is the Audio Resource ID
<loop> is 0 for no looping, 1 to loopthe starting Y coordinate
Notes: The play instruction is used to configure and start audio playback. audio0 and audio1 are used to control the channel. Audio playback is global and playback continues after leaving and changing pages, if you want the audio to stop on leaving the page, you should do so in the page leave event
play 1,3,0// play resource 3 on channel 1 with no looping
play 0,2,1// play resource 2 on channel 0 with looping
36twfile2 Advanced. Transfer file over Serial
usage: twfile <filepath>,<filesize>
<filepath> is destination path and filename quote encapsulated text
<filesize> is the size of the file in bytes.
twfile “ram/0.jpg”,1120// transfer jpg over serial to ram/0.jpg size 1120 bytes
twfile “sd0/0.jpg”,1120// transfer jpg over serial to sd0/0.jpg size 1120 bytes
37delfile1 Advanced. Delete external file.
usage: delfile <filepath>
<filepath> is target path and filename as quote encapsulated text
delfile “ram/0.jpg”// remove transferred file ram/0.jpg
delfile “sd0/0.jpg”// remove transferred file sd0/0.jpg
38refile2 Advanced. Rename external file.
usage: refile <oldname>,<newname>
<oldname> is source path and filename as quote encapsulated text
<newname> is target path and filename as quote encapsulated text
refile “ram/0.jpg”,”ram/1.jpg”// rename file ram/0.jpg to ram/1.jpg
refile “sd0/0.jpg”,”sd0/1.jpg”// rename file sd0/0.jpg to sd0/1.jpg
39findfile2 Advanced. Find File reports if named external file exists
usage: findfile <pathfile>,<result>
<pathfile> is source path and filename as quote encapsulated text
<result> is a numeric attribute for the result to be stored
Returns 0 result if find fails, returns 1 if find is successful.
findfile “ram/0.jpg”,n0.val// check if file exists, store result in n0.val
findfile “sd0/0.jpg”,sys0//check if file exists, store result in sys0
40rdfile4 Advanced. Read File contents and outputs contents over serial
usage: rdfile <pathfile>,<offset>,<count>,<crc>
<pathfile> is source path and filename as quote encapsulated text
<offset> is the starting offset of the file
<count> is number of bytes to return (see note if 0)
<crc> is an option (0: no crc, 1: Modbus crc16, 10: crc32)
If count is 0, then 4 byte file size is returned in little endian order.
rdfile “ram/0.jpg”,0,10,0// send first 10 bytes of file, no CRC, 10 bytes.
rdfile “sd0/0.jpg”,0,10,1// send first 10 bytes of file, MODBUS CRC, 12 bytes.
rdfile “sd0/0.jpg”,0,10,10// send first 10 bytes of file, CRC32, 14 bytes.
41setlayer2 Set Component Layer
usage: setlayer <comp1>,<comp2>
<comp1> is component ID or objname of component needing to change layers
<comp2> is the component ID or object name comp1 is placed above
Note: using comp2 value of 255 places comp1 on topmost layer.
setlayer t0,n0//places to above n0’s layer
setlayer t0,255//place t0 on the topmost layer
setlayer n0,3//place n0 on the 3rd layer
42newdir1 Advanced. Create a new directory
usage: newdir <dir>
<dir> is directory to be created
Note: directory name to end with forward slash /
newdir “sd0/data/”//create directory called data
newdir “sd0/202003/”//create directory called 202003
43deldir1 Advanced. Remove a directory
usage: deldir <dir>
<dir> is directory to be deleted
Note: directory name to end with forward slash /
deldir “sd0/data/”//remove directory called data
deldir “sd0/202003/”//remove directory called 202003
44redir2 Advanced. Rename a directory
usage: redir <srcdir>,<destdir>
<srcdir> is directory to be renamed
<destdir> new name of directory being renamed
Note: directory names to end with forward slash /
redir “sd0/data/”,”sd0/data2/”//rename data to data2
redir “sd0/202003/”,”sd0/2004/”//rename 202003 to 2004
45finddir2 Advanced. Test if directory exists
usage: finddir <dir>,<attr>
<dir> is directory to test if exists
<attr> number variable where result will be stored
Note: directory names to end with forward slash /
Returns 1 if directory exists, returns 0 if not found
finddir “sd0/data/”,va0.val//find directory data, result in va0.val
finddir “sd0/2003/”,sys0//find directory 2004, result in sys0
46udelete1 Advanced. Remove bytes from Serial Buffer
usage: udelete <qty>
<qty> is number of bytes to remove from beginning of Serial Buffer
Note: Protocol Reparse Mode (recmod) must be active to be used. Most HMI applications will not require Protocol Reparse and should be skipped if not fully understood.
udelete 24//delete first 24 bytes of Buffer
udelete 10//delete first 10 bytes of Buffer
47crcrest2 Advanced. Reset CRC and Initialize
usage: crcrest <crctype>,<initval>
<crctype> must be 1 (type Modbus CRC16)
<initval> is crc initial value (usually 0xFFFF)
crcrest 1,0xFFFF//reset and initialize crc
48crcputs2 Advanced. Accumulate CRC for Variable or constant
usage: crcputs <attr>,<length>
<attr> is attribute or constant
<length> is 0 (for Automatic) or specified length
crcputs va0.val,0//accumulate crc for va0.val (length auto)
crcputs va1.txt,3//accumulate crc for first 3 bytes of va1.txt
49crcputh1 Advanced. Accumulate CRC for hex string
usage: crcputh <hex>
<hex> is string of hex chars
Note: each byte in the hex string has 2 hexdigits, bytes separated by a space.
crcputh 0A//accumulate crc for byte 0x0A
crcputh 0A 0D//accumulate crc for bytes 0x0A 0x0D
50crcputu2 Advanced. Accumulate CRC on Serial Buffer
usage: crcputu <start>,<qty>
<start> is start byte of Serial Buffer to accumulate
<qty> is number of bytes to accumulate including start byte
Note: Protocol Reparse Mode (recmod) must be active to be used. Most HMI applications will not require Protocol Reparse and should be skipped if not fully understood.
crcputu 0,10//accumulate crc for first 10 bytes of Serial Buffer
crcputu 10,10//accumulate crc for second 10 bytes 0x0A 0x0D
51spstr4 Split String
usage: spstr <src>,<dest>,<key>,<index>
<src> is src .txt attribute or string data constant
<dest> is .txt attribute where result is stored
<key> is the text delimiter encapsulated in double quotes
<index> is zero-indexed iteration result to return
spstr “ab3cd3ef3ghi”,va1.txt,”3″,0//return string ab before first delimiter occurs
spstr “ab3cd3ef3ghi”,va1.txt,”3″,2//return string ef after second delimiter occurs

4 – GUI Designing Commands

No.NameParam
Count
Description and Usage/Parameters/Examples
1cls1 Clear the screen and fill the entire screen with specified color
usage: cls <color>
<color> is either decimal 565 Color Value or Color Constant
cls BLUE // Clear the screen and fill with color BLUE
cls 1024 // Clear the screen and fill with color 1024
2pic3 Display a Resource Picture at specified coordinate
usage: pic <x>,<y>,<picid>
<x> is the x coordinate of upper left corner where picture should be drawn
<y> is the y coordinate of upper left corner where picture should be drawn
<picid> is the number of the Resource Picture in the HMI design
pic 10,20,0 // Display Resource Picture #0 with upper left corner at (10,20)
pic 40,50,1 // Display Resource Picture #1 with upper left corner at (40,50)
3picq5 Crop Picture area from Resource Picture using defined area
– replaces defined area with content from the same area of Resource Picture
– Resource Picture should be full screen-size or area might be undefined
usage: picq <x>,<y>,<w>,<h>,<picid>
<x> is the x coordinate of upper left corner of defined crop area
<y> is the y coordinate of upper left corner of defined crop area
<w> is the width of the defined crop area
<h> is the height of the defined crop area
<picid> is the number of the Resource Picture in the HMI design
picq 20,50,30,20,0
// crops area 30×20, from (20,50) to (49,69), from Resource Picture 0
4xpic7 Advanced Crop Picture
crop area from source Resource Picture render at destination coordinate
usage: xpic <destx>,<desty>,<w>,<h>,<srcx>,<srcy>,<picid>
<destx> is the x coordinate of destination upper left corner
<desty> is the y coordinate of destination upper left corner
<w> is the width of the defined crop area
<h> is the height of the defined crop area
<srcx> is the x coordinate of upper left corner of defined crop area
<srcy> is the y coordinate of upper left corner of defined crop area
<picid> is the number of the Resource Picture in the HMI design
xpic 20,50,30,20,15,15,0 // crops area 30×20, from (15,15) to (44,34),
// from Resource Picture 0 and renders it with upper left corner at (20,50)
5xstr11 Prints text on the Nextion device using defined area for text rendering
usage: xstr <x>,<y>,<w>,<h>,<font>,<pco>,<bco>,<xcen>,<ycen>,<sta>,<text>
<x> is the x coordinate of upper left corner of defined text area
<y> is the y coordinate of upper left corner of defined text area
<w> is the width of the defined text area
<h> is the height of the defined text area
<font> is the number of the Resource Font
<pco> is the foreground color of text (Color Constant or 565 color value)
<bco> is a) background color of text, or b) picid if <sta> is set to 0 or 2
<xcen> is the Horizontal Alignment (0 – left, 1 – centered, 2 – right)
<ycen> is the Vertical Alignment (0 – top/upper, 1 – center, 3 – bottom/lower)
<sta> is background Fill (0 – crop image, 1 – solid color, 2 – image, 3 – none)
<text> is the string content (constant or .txt attribute), ie “China”, or va0.txt
xstr 10,10,100,30,1,WHITE,GREEN,1,1,1,va0.txt
// use are 100×30 from (10,10) to (109,39) to print contents of va0.txt using
// Font Resource 1 rendering Green letters on White background with both
// horizontal and vertical centering and sta set as solid-color.
6fill5 Fill a defined area with specified color
usage: fill <x>,<y>,<w>,<h>,<color>
<x> is the x coordinate of upper left corner of defined fill area
<y> is the y coordinate of upper left corner of defined fill area
<w> is the width of the defined fill area
<h> is the height of the defined fill area
<color> is fill color, either decimal 565 Color Value or Color Constant
fill 20,20,150,50,1024
// fills area 150×50 from (20,20) to (169,69) with 565 Color 1024.
7line5 Draw a line from point to point with specified color
usage: line <x1>,<y1>,<x2>,<y2>,<color>
<x1> is the x coordinate of the starting point of the line to be drawn
<y1> is the y coordinate of the starting point of the line to be drawn
<x2> is the x coordinate of the ending point of the line to be drawn
<y2> is the y coordinate of the ending point of the line to be drawn
<color> is line color, either decimal 565 Color Value or Color Constant
line 20,30,170,200,BLUE // draws line in BLUE from (20,30) to (170,200)
8draw5 Draw a hollow rectangle around specified area with specified color
usage: draw <x1>,<y1>,<x2>,<y2>,<color>
<x1> is the x coordinate of the upper left corner of rectangle area
<y1> is the y coordinate of the upper left corner of rectangle area
<x2> is the x coordinate of the lower right corner of rectangle area
<y2> is the y coordinate of the lower right corner of rectangle area
<color> is line color, either decimal 565 Color Value or Color Constant
draw 10,10,70,70,GREEN // draw a Green rectangle around (10,10) to (79,79)
// effectively four lines from (x1,y1) to (x2,y1) to (x2,y2) to (x1,y2) to (x1,y1)
9cir4 Draw a hollow circle with specified radius and specified color
usage: cir <x>,<y>,<radius>,<color>
<x> is the x coordinate of the center point for the circle
<y> is the y coordinate of the center point for the circle
<radius> is the radius in pixels
<color> is line color, either decimal 565 Color Value or Color Constant
cir 100,100,30,RED // renders a hollow Red circle with circle center at (100,100),
// a 30 pixel radius, a 61 pixel diameter, within boundary (70,70) to (130,130).
10cirs4 Draw a filled circle with specified radius and specified color
usage: cirs <x>,<y>,<radius>,<color>
<x> is the x coordinate of the center point for the circle
<y> is the y coordinate of the center point for the circle
<radius> is the radius in pixels
<color> is fill color, either decimal 565 Color Value or Color Constant
cirs 100,100,30,RED // renders a filled Red circle with center at (100,100),
// a 30 pixel radius, a 61 pixel diameter, within boundary (70,70) to (130,130).

5 – Color Code Constants

No.Constant565 Color ValueIndicator Color
1 BLACK0Black
2 BLUE31Blue
3 BROWN48192Brown
4 GREEN2016Green
5 YELLOW65504Yellow
6 RED63488Red
7 GRAY33840Gray
8 WHITE65535White
Note:16-bit 565 Colors are in decimal values from 0 to 65535
24-bit RGB 11011000 11011000 11011000
16-bit 565 11011 110110 11011

6 – System Variables

No.NameMeaningExample/Description
1dpCurrent
Page ID
dp=1, n0.val=dp
read: Contains the current page displayed as per the HMI design
write: change page to value specified (same effect as page command)
min 0, max # of highest existing page in the user’s HMI design.
2dim
dims
Nextion
Backlight
dim=32, dims=100
Sets the backlight level in percent
min 0, max 100, default 100 or user defined
Note: dim=32 will set the current backlight level to 32%.
using dims=32 will set the current backlight level to 32% and save this to be new power on default backlight level, persisting until changed.
3baud
bauds
Nextion
Baud Rate
baud=9600, bauds=9600
Sets the Nextion Baud rate in bits-per-second
min 2400, max 921600, default 9600 or user defined
Valid values are: 2400, 4800, 9600, 19200, 31250, 38400, 57600, and 115200, 230400, 250000, 256000, 512000, and 921600
Note: baud=38400 will set the current baud rate to 38400
using bauds=38400 will set the current baud rate to 38400 and save this to be new power on default baud rate, persisting until changed.
Note: on rare occasions bauds has become lost. With the addition of the Editor Program.s feature, it is now recommended to specify your desired baud rate baud=9600 between declarations and before the page0 instruction and no longer recommending inserting bauds=9600 in the first page’s Preinitialization Event of the HMI.
4spax
spay
Font
Spacing
spax=2, spay=2
Sets the default rendering space for xstr:
horizontally between font characters with spax additional pixels and
vertically between rows (if multi-lined) with spay additional pixels.
min 0, max 65535, default 0
Note: Components now have their own individual .spax/.spay attributes that are now used to determine spacing for the individual component.
5thcTouch
Draw Brush
Color
thc=RED, thc=1024
Sets the Touch Drawing brush color
min 0, max 65535, default 0
Valid choices are either color constants or the decimal 565 color value.
6thdraTouch
Drawing
thdra=1 (on), thdra=0 (off)
Turns the internal drawing function on or off.
min 0, max 1, default 0
When the drawing function is on, Nextion will follow touch dragging with the current brush color (as determined by the thc variable).
7usspSleep on
No Serial
ussp=30
Sets internal No-serial-then-sleep timer to specified value in seconds
min 3, max 65535, default 0 (max: 18 hours 12 minutes 15 seconds)
Nextion will auto-enter sleep mode if and when this timer expires.
Note: Nextion device needs to exit sleep to issue ussp=0 to disable sleep on no serial, otherwise once ussp is set, it will persist until reboot or reset.
8thspSleep on
No Touch
thsp=30
Sets internal No-touch-then-sleep timer to specified value in seconds
min 3, max 65535, default 0 (max: 18 hours 12 minutes 15 seconds)
Nextion will auto-enter sleep mode if and when this timer expires.
Note: Nextion device needs to exit sleep to issue thsp=0 to disable sleep on no touch, otherwise once thsp is set, it will persist until reboot or reset.
9thupAuto Wake
on Touch
thup=0 (do not wake), thup=1 (wake on touch)
Sets if Nextion should auto-wake from sleep when touch press occurs.
min 0, max 1, default 0
When value is 1 and Nextion is in sleep mode, the first touch will only trigger the auto wake mode and not trigger a Touch Event.
thup has no influence on sendxy, sendxy will operate independently.
10sendxyRealTime
Touch
Coordinates
sendxy=1 (start sending) sendxy=0 (stop sending)
Sets if Nextion should send 0x67 and 0x68 Return Data
min 0, max 1, default 0
– Less accurate closer to edges, and more accurate closer to center.
Note: expecting exact pixel (0,0) or (799,479) is simply not achievable.
11delayDelaydelay=100
Creates a halt in Nextion code execution for specified time in ms
min 0, max 65535
As delay is interpreted, a total halt is avoided. Incoming serial data is received and stored in buffer but not be processed until delay ends. If delay of more than 65.535 seconds is required, use of multiple delay statements required.
delay=-1 is max. 65.535 seconds.
12sleepSleepsleep=1 (Enter sleep mode) or sleep=0 (Exit sleep mode)
Sets Nextion mode between sleep and awake.
min 0, max 1, or default 0
When exiting sleep mode, the Nextion device will auto refresh the page
(as determined by the value in the wup variable) and reset the backlight brightness (as determined by the value in the dim variable). A get/print/printh/wup/sleep instruction can be executed during sleep mode. Extended IO binding interrupts do not occur in sleep.
13bkcmdPass / Fail
Return Data
bkcmd=3
Sets the level of Return Data on commands processed over Serial.
min 0, max 3, default 2
– Level 0 is Off – no pass/fail will be returned
– Level 1 is OnSuccess, only when last serial command successful.
– Level 2 is OnFailure, only when last serial command failed
– Level 3 is Always, returns 0x00 to 0x23 result of serial command.
Result is only sent after serial command/task has been completed, as such this provides an invaluable status for debugging and branching. Table 2 of Section 7 Nextion Return Data is not subject to bkcmd
14randRandom
Value
n0.val=rand
Readonly. Value returned by rand is random every time it is referred to.
default range is -2147483648 to 2147483647
range of rand is user customizable using the randset command
range as set with randset will persist until reboot or reset
15sys0
sys1
sys2
Numeric
System
Variables
sys0=10 sys1=40 sys2=60 n0.val=sys2
System Variables are global in nature with no need to define or create.
They can be read or written from any page. 32-bit signed integers.
min value of -2147483648, max value of 2147483647
Suggested uses of sys variables include
– as temporary variables in complex calculations
– as parameters to pass to click function or pass between pages.
16wupWake Up
Page
wup=2, n0.val=wup
Sets which page Nextion loads when exiting sleep mode
min is 0, max is # of last page in HMI, or default 255
When wup=255 (not set to any existing page)
– Nextion wakes up to current page, refreshing components only
wup can be set even when Nextion is in sleep mode
17usupWake On
Serial Data
usup=0, usup=1
Sets if serial data wakes Nextion from sleep mode automatically.
min is 0, max is 1, default 0
When usup=0, send sleep=0ÿÿÿ to wake Nextion
When usup=1, any serial received wakes Nextion
18rtc0
rtc1
rtc2
rtc3
rtc4
rtc5
rtc6
RTCrtc0=2017, rtc1=8, rtc2=28,
rtc3=16, rtc4=50, rtc5=36, n0.val=rtc6
Nextion RTC:
rtc0 is year 2000 to 2099, rtc1 is month 1 to 12, rtc2 is day 1 to 31,
rtc3 is hour 0 to 23, rtc4 is minute 0 to 59, rtc5 is second 0 to 59.
rtc6 is dayofweek 0 to 6 (Sunday=0, Saturday=6)
rtc6 is readonly and calculated by RTC when date is valid.
19pio0
pio1
pio2
pio3
pio4
pio5
pio6
pio7
GPIOpio3=1, pio3=0, n0.val=pio3
Default mode when power on: pull up input mode
Internal pull up resistor. GPIO voltage level is 3.3V and previous documentation stated as 50K (Ω) Pullup resistance, is defined now in a bit more detail. As with any MCU there is short period of uncertain level on Power On between when the MCU can begin default pullup assertions, and after this then the user configuration is asserted (cfgpio instructions). For the smaller Enhanced Series (K024,K028,K032 @ 48MHz): Pullup resistance on the Enhanced is more precisely defined as Typical 40kΩ with Min 25kΩ Max 55kΩ. For the larger Enhanced Series (K035,K043,K050,K070 @ 108MHz): Pullup resistance on the larger Enhanced is more precisely defined as Typical 40kΩ with Min 30kΩ Max 50kΩ. For the Intelligent Series (all models @ 200Mhz): the pullup resistance is more precisely defined as Typical 66kΩ with Min 53kΩ and Max 120kΩ.
GPIO is digital. Value of 0 or 1 only.
– refer to cfgpio command for setting GPIO mode
read if in input mode, write if in output mode
19pwm4
pwm5
pwm6
pwm7
PWM Duty
Cycle
pwm7=25
Value in percentage. min 0, max 100, default 50.
– refer to cfgpio command for setting GPIO mode
supports pwm4, pwm5, pwm6 and pwm7
supports only pwm6 and pwm7
21pwmfPWM
Frequency
pwmf=933
Value is in Hz. min value 1 Hz, max value 65535 Hz. default 1000 Hz
All PWM output is unified to only one Frequency, no independent individual settings are allowed.
– refer to cfgpio command for setting GPIO mode
22addrAddressaddr=257
Advanced. Enables/disables Nextion’s two byte Address Mode
0, or min value 256, max value 2815. default 0
Setting addr will persist to be the new power-on default.
– refer to section 1.19
23tch0
tch1
tch2
tch3
Touch
Coordinates
x.val=tch0, y.val=tch1
Readonly. When Pressed tch0 is x coordinate, tch1 is y coordinate.
When released (not currently pressed), tch0 and tch1 will be 0.
tch2 holds the last x coordinate, tch3 holds the last y coordinate.
24recmodProtocol Reparserecmod=0, recmod=1
Advanced. Set passive or active Protocol Reparse mode.
min is 0, max is 1, default 0
When recmod=0, Nextion is in passive mode and processes serial data according to the Nextion Instruction Set, this is the default power on processing. When recmod=1, Nextion enters into active mode where the serial data waits to be processed by event code. Most HMI applications will not require Protocol Reparse and should be skipped if not fully understood.
25usizeBytes in Serial Buffern0.val=usize
Advanced. Read Only. Valid in active Protocol Reparse mode.
min is 0, max is 1024
When Nextion is in active Protocol Reparse mode, usize reports the number of available bytes in the serial buffer. Most HMI applications will not require Protocol Reparse and should be skipped if not fully understood.
26u[index]Serial Buffer Datan0.val=u[0]
Advanced. Read Only. Valid in active Protocol Reparse mode.
min is 0, max is 255
When Nextion is in active Protocol Reparse mode, the u[index] array returns the byte at position index from the serial buffer. Most HMI applications will not require Protocol Reparse and should be skipped if not fully understood.
27eql
eqm
eqh
Equalizer Groupingseqm=7
Valid on Nextion Device, not supported in Debug Simulator.
min is 0, max is 15
eql: Bass (31Hz to 125Hz, eq0..eq2)
eqm: Midrange (250Hz to 2000Hz, eq3..eq6)
eqh: Treble (4000Hz to 1600Hz, eq7..eq9)
Setting to 7 is Balanced with no attenuation, no gain
Setting 0..6, the lower the value the higher the attenuation
Setting 8..15, the higher the value the higher the gain
NOTE: The base of the equalizer is operated according to eq0..eq9,
when a group is modified the corresponding individual bands are modified, however modifying an individual band does not modify the group. (ie: setting eql=4 sets eq0, eq1 and eq2 to 4, but setting eq1=3 does not modify eql to 3, eq0 and eq2 remain at 4).
28eq0
eq1
eq2
eq3
eq4
eq5
eq6
eq7
eq8
eq9
Equalizer
Individual
Bands
eq6=7
Valid on Nextion Device, not supported in Debug Simulator.
min is 0, max is 15
eq0 (31Hz), eq1 (62Hz), eq2 (125Hz),
eq3 (250Hz), eq4 (500Hz), eq5 (1000Hz), eq6 (2000Hz),
eq7 (4000Hz), eq8 (8000Hz), eq9 (16000Hz)
Setting to 7 is Balanced with no attenuation, no gain
Setting 0..6, the lower the value the higher the attenuation
Setting 8..15, the higher the value the higher the gain
NOTE: The base of the equalizer is operated according to eq0..eq9,
when a group is modified the corresponding individual bands are modified, however modifying an individual band does not modify the group. (ie: setting eql=4 sets eq0, eq1 and eq2 to 4, but setting eq1=3 does not modify eql to 3, eq0 and eq2 remain at 4).
29volumeAudio Volumevolume=60
Valid on Nextion Device, not supported in Debug Simulator.
min is 0, max is 100
volume persists and sets the power-on default setting for the audio volume
30audio0
audio1
Audio Channel Controlaudio0=0// stop channel 0 audio playback

min is 0, max is 2
0 (stop), 1 (resume), 2 (pause).
Notes: The play instruction is used to configure and start audio playback. audio0 and audio1 are only used to control the channel. Only if the channel is paused can it be resumed, if the channel is stopped then the play instruction is required to start it again. Audio playback is global and playback continues after leaving and changing pages, if you want the channel to stop on leaving the page, you must do so in the page leave event
31crcvalCRC Valuex.val=crcval
Readonly. Holds the current CRC accumulated value.
Use crcrest to reset and initialize
Use crcputs, crcputh or crcputu to accumulate
32lowpowerLow PowerDiscovery Series. Low Power 0.25mA deep sleep
Sets if Nextion should enter deep sleep mode on sleep command.
min 0, max 1, default 0
lowpower=0 (normal operations), lowpower=1 (deep sleep enabled)
In deep sleep mode, the wake-up time will be longer, the data will likely be lost when the serial power is receivng the wake-up command. It is recommended to send an empty command (termination NIS 1.1) and wait 500ms before operations.

7 – Format of Nextion Return Data

Return Codes dependent on bkcmd value being greater than 0
No.BytebkcmdlenMeaningFormat/Description
10x00
2,34Invalid Instruction0x00 0xFF 0xFF 0xFF
Returned when instruction sent by user has failed
20x01
1,34Instruction Successful0x01 0xFF 0xFF 0xFF
Returned when instruction sent by user was successful
30x02
2,34Invalid Component ID0x02 0xFF 0xFF 0xFF
Returned when invalid Component ID or name was used
40x03
2,34Invalid Page ID0x03 0xFF 0xFF 0xFF
Returned when invalid Page ID or name was used
50x04
2,34Invalid Picture ID0x04 0xFF 0xFF 0xFF
Returned when invalid Picture ID was used
60x05
2,34Invalid Font ID0x05 0xFF 0xFF 0xFF
Returned when invalid Font ID was used
70x06
2,34Invalid File Operation0x06 0xFF 0xFF 0xFF
Returned when File operation fails
80x09
2,34Invalid CRC0x09 0xFF 0xFF 0xFF
Returned when Instructions with CRC validation fails their CRC check.
When using instructions with CRC termination (0xFE 0xFE 0xFE) and an incorrectly calculated CRC is sent with the Instruction, this error will be returned regardless of the bkcmd setting
90x11
2,34Invalid Baud rate Setting0x11 0xFF 0xFF 0xFF
Returned when invalid Baud rate was used
100x12
2,34Invalid Waveform ID or Channel #0x12 0xFF 0xFF 0xFF
Returned when invalid Waveform ID or Channel # was used
110x1A
2,34Invalid Variable name or attribute0x1A 0xFF 0xFF 0xFF
Returned when invalid Variable name or invalid attribute was used
120x1B
2,34Invalid Variable Operation0x1B 0xFF 0xFF 0xFF
Returned when Operation of Variable is invalid. ie: Text assignment t0.txt=abc or t0.txt=23, Numeric assignment j0.val=”50″ or j0.val=abc
130x1C
2,34Assignment failed to assign0x1C 0xFF 0xFF 0xFF
Returned when attribute assignment failed to assign
140x1D
2,34EEPROM Operation failed0x1D 0xFF 0xFF 0xFF
Returned when an EEPROM Operation has failed
150x1E
2,34Invalid Quantity of Parameters0x1E 0xFF 0xFF 0xFF
Returned when the number of instruction parameters is invalid
160x1F
2,34IO Operation failed0x1F 0xFF 0xFF 0xFF
Returned when an IO operation has failed
170x20
2,34Escape Character Invalid0x20 0xFF 0xFF 0xFF
Returned when an unsupported escape character is used
180x23
2,34Variable name too long0x23 0xFF 0xFF 0xFF
Returned when variable name is too long. Max length is 29 characters: 14 for page + “.” + 14 for component.

Return Codes not affected by bkcmd value, valid in all cases
No.BytelengthMeaningFormat/Description
190x00
6Nextion Startup0x00 0x00 0x00 0xFF 0xFF 0xFF
Returned when Nextion has started or reset. Since Nextion Editor v1.65.0, the Startup preamble is not at the firmware level but has been moved to a printh statement in Program.s allowing a user to keep, modify or remove as they choose.
200x24
4Serial Buffer Overflow0x24 0xFF 0xFF 0xFF
Returned when a Serial Buffer overflow occurs
Buffer will continue to receive the current instruction, all previous instructions are lost.
210x65
7Touch Event0x65 0x00 0x01 0x01 0xFF 0xFF 0xFF
Returned when Touch occurs and component’s
corresponding Send Component ID is checked
in the users HMI design.
0x00 is page number, 0x01 is component ID,
0x01 is event (0x01 Press and 0x00 Release)
data: Page 0, Component 1, Pressed
220x66
5Current Page Number0x66 0x01 0xFF 0xFF 0xFF
Returned when the sendme command is used.
0x01 is current page number
data: page 1
230x67
9Touch Coordinate (awake)0x67 0x00 0x7A 0x00 0x1E 0x01 0xFF 0xFF 0xFF
Returned when sendxy=1 and not in sleep mode
0x00 0x7A is x coordinate in big endian order,
0x00 0x1E is y coordinate in big endian order,
0x01 is event (0x01 Press and 0x00 Release)
(0x00*256+0x71,0x00*256+0x1E)
data: (122,30) Pressed
240x68
9Touch Coordinate (sleep)0x68 0x00 0x7A 0x00 0x1E 0x01 0xFF 0xFF 0xFF
Returned when sendxy=1 and exiting sleep
0x00 0x7A is x coordinate in big endian order,
0x00 0x1E is y coordinate in big endian order,
0x01 is event (0x01 Press and 0x00 Release)
(0x00*256+0x71,0x00*256+0x1E)
data: (122,30) Pressed
250x70
VariedString Data Enclosed0x70 0x61 0x62 0x31 0x32 0x33 0xFF 0xFF 0xFF
Returned when using get command for a string.
Each byte is converted to char.
data: ab123
260x71
8Numeric Data Enclosed0x71 0x01 0x02 0x03 0x04 0xFF 0xFF 0xFF
Returned when get command to return a number
4 byte 32-bit value in little endian order.
(0x01+0x02*256+0x03*65536+0x04*16777216)
data: 67305985
270x86
4Auto Entered Sleep Mode0x86 0xFF 0xFF 0xFF
Returned when Nextion enters sleep automatically
Using sleep=1 will not return an 0x86
280x87
4Auto Wake from Sleep0x87 0xFF 0xFF 0xFF
Returned when Nextion leaves sleep automatically
Using sleep=0 will not return an 0x87
290x88
4Nextion Ready0x88 0xFF 0xFF 0xFF
Returned when Nextion has powered up and is now initialized successfully. Since Nextion Editor v1.65.0, the Nextion Ready is not at the firmware level but has been moved to a printh statement in Program.s allowing a user to keep, modify or remove as they choose.
300x89
4Start microSD Upgrade0x89 0xFF 0xFF 0xFF
Returned when power on detects inserted microSD
and begins Upgrade by microSD process
310xFD
4Transparent Data Finished0xFD 0xFF 0xFF 0xFF
Returned when all requested bytes of Transparent
Data mode have been received, and is now leaving transparent data mode (see 1.16)
320xFE
4Transparent Data Ready0xFE 0xFF 0xFF 0xFF
Returned when requesting Transparent Data
mode, and device is now ready to begin receiving
the specified quantity of data (see 1.16)