Hey Guys, This is another quick update on the Nextion Interface Setup and I will also demonstrate it in the video below.
As I have Blogged in my previous blogs that the RX Interrupt on Nextion display was not working and I had planned for a Parallel bus handshake between STM32 and Arduino Nano while leaving the Rx decoding part with Arduino Nano.
The primary reason of the Rx Interrupt failure was lack of Buffered Serial Library implementation for STM32L476R Nucleo. After couple of failed attempts of implementation myself I had to fall back on the previously mentioned method.
So, The way to approach was to Decode the incoming messages from the Nextion Display in Arduino and convert the data into Parallel bus oaf Arduino which we can further poll in Perodic Routine of STM32.
Arduino Code - For Converting the Nextion messages to Parallel bus For Arduino NANO
NOTE : I am using Official Nextion Libraries 
Nextion messages look something like This
0X65 0X00 0X02 0X01 0XFF 0XFF 0XFF
and details on each subsection can be found on the Nextion Instruction Set Page
#include
#include "Timer.h"
#include
SoftwareSerial nextion(2, 3);// Nextion TX to pin 2 and RX to pin 3 of Arduino
Nextion myNextion(nextion, 9600); //create a Nextion object named myNextion using the nextion serial port @ 9600bps
Timer t;
void setup() {
Serial.begin(9600);
myNextion.init();
pinMode(4,OUTPUT); // Display Boot Successful
digitalWrite(4,LOW);
pinMode(5,OUTPUT); // Ride Screen
digitalWrite(5,LOW);
pinMode(6,OUTPUT); // Bump Pressed
digitalWrite(6,LOW);
pinMode(7,OUTPUT); // Self Check Screen
digitalWrite(7,LOW);
pinMode(8,OUTPUT); // Music Screen
digitalWrite(8,LOW);
pinMode(9,OUTPUT); // Music Left
digitalWrite(9,LOW);
pinMode(10,OUTPUT); // Music Play Pause
digitalWrite(10,LOW);
pinMode(11,OUTPUT); // Music Right
digitalWrite(11,LOW);
t.every(1000, resetAll);
}
void loop() {
String message = myNextion.listen(); //check for message
if(message != ""){ // if a message is received...
if( message == "6"){
Serial.println("Booted");
digitalWrite(6,HIGH);
}else if (message == '0xFF'){
Serial.println("Off");
digitalWrite(4,LOW);
// Ride Screen
digitalWrite(5,LOW);
// Options Screen
digitalWrite(6,LOW);
// Self Check Screen
digitalWrite(7,LOW);
// Music Screen
digitalWrite(8,LOW);
// Music Left
digitalWrite(9,LOW);
// Music Play Pause
digitalWrite(10,LOW);
// Music Right
digitalWrite(11,LOW);
}else if (message == "7"){
Serial.println("Riding Screen");
digitalWrite(5,HIGH);
}else if (message == "65 7 6 0 ffff ffff ffff"){
Serial.println("Bump Pressed");
digitalWrite(6,HIGH);
}else if (message == "8"){
Serial.println("Music Controls");
digitalWrite(8,HIGH);
}else if (message == "65 8 4 0 ffff ffff ffff"){
Serial.println("Left Button");
digitalWrite(9,HIGH);
}else if (message == "65 8 5 0 ffff ffff ffff"){
Serial.println("Play Pause Button");
digitalWrite(10,HIGH);
}else if (message == "65 8 3 0 ffff ffff ffff"){
Serial.println("Right Button");
digitalWrite(11,HIGH);
}else if (message == "3"){
Serial.println("Self Check Page");
digitalWrite(7,HIGH);
}else {
Serial.println("INVALID INPUT");
digitalWrite(4,LOW);
// Ride Screen
digitalWrite(5,LOW);
// Options Screen
digitalWrite(6,LOW);
// Self Check Screen
digitalWrite(7,LOW);
// Music Screen
digitalWrite(8,LOW);
// Music Left
digitalWrite(9,LOW);
// Music Play Pause
digitalWrite(10,LOW);
// Music Right
digitalWrite(11,LOW);
}
Serial.println(message); //...print it out
}
}
void resetAll(void){
digitalWrite(4,LOW);
// Ride Screen
digitalWrite(5,LOW);
// Options Screen
digitalWrite(6,LOW);
// Self Check Screen
digitalWrite(7,LOW);
// Music Screen
digitalWrite(8,LOW);
// Music Left
digitalWrite(9,LOW);
// Music Play Pause
digitalWrite(10,LOW);
// Music Right
digitalWrite(11,LOW);
Serial.println("Reset All Lines");
}
Further Here are some Code snippets for my Perodic function checking the Arduino Lines
DEFINING THE BUS
DigitalIn dispBoot(PC_4); // Connected to D4 :: Display Boot Sucessful DigitalIn mPnP(PB_1); // Connected to D10 :: Music PLay n Pause DigitalIn mRt(PB_2); // Connected to D11 :: Music Rt DigitalIn rideS(PB_11); // Connected to D5 :: Ride Screen DigitalIn bumpP(PB_12); // Connected to D6 :: Bump Pressed DigitalIn scS(PB_13); // Connected to D7 :: Self Check Screen DigitalIn musicS(PB_14); // Connected to D8 :: Music Screen DigitalIn mLt(PB_15); // Connected to D9 :: Music Left
Checking the bus in Preodic()
// Screen and Controlls Checks
if(dispBoot){
nextionBoot = true;
nextionScreen ='B';
}else if(rideS){
nextionScreen ='R';
}else if(bumpP){
nextionScreen ='B';
}else if(musicS){
nextionScreen ='M';
}else if(scS){
nextionScreen ='S';
}
if(mPnP){
nextionMusic ='P';
}else if(mLt){
nextionMusic ='L';
}else if(mRt){
nextionMusic ='R';
}
//Update the Display Screen
if(nextionScreen =='R') { // checking if nextio display is on rise screen
nextion.printf(dispSpeed); // updating Speed Value on Nextion Display
nextion.printf("%d",(int)(ridingSpeed));
nextion.printf("%c%c%c",terminator,terminator,terminator);
nextion.printf(dispAvg); // updating Avg Speed Value on Nextion Display
nextion.printf("%d",(int)(avgSpeedF));
nextion.printf("%c%c%c",terminator,terminator,terminator);
nextion.printf(dispDist); // updating Distance Value on Nextion Display
nextion.printf("%d",(int)(totalDist));
nextion.printf("%c%c%c",terminator,terminator,terminator);
}else if(nextionScreen =='S' && scS){
if(hum_temp->read_id(&id)){
nextion.printf(hx_check);
nextion.printf(pass);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}else {
nextion.printf(hx_check);
nextion.printf(fail);
nextion.printf("%c%c%c",terminator,terminator,terminator);
nextion.printf(temp_check);
nextion.printf(fail);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}
if(press_temp->read_id(&id)){
nextion.printf(bx_check);
nextion.printf(pass);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}else{
nextion.printf(bx_check);
nextion.printf(fail);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}
if(magnetometer->read_id(&id)){
nextion.printf(temp_check);
nextion.printf(pass);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}else {
nextion.printf(temp_check);
nextion.printf(fail);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}
if(accelerometer->read_id(&id)){
nextion.printf(accl_check);
nextion.printf(pass);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}else {
nextion.printf(accl_check);
nextion.printf(fail);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}
if(acc_gyro->read_id(&id)){
nextion.printf(gyro_check);
nextion.printf(pass);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}else{
nextion.printf(gyro_check);
nextion.printf(fail);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}
if(BLEStat){
nextion.printf(ble_check);
nextion.printf(pass);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}else{
nextion.printf(ble_check);
nextion.printf(fail);
nextion.printf("%c%c%c",terminator,terminator,terminator);
}
while(scS);
}
Thanks For Watching
Regards,
GS Gill