I would like to send a PPM with M5 stack Fire

[A Former User]

HI,
after to consult many web page I don't find a solution
I would like to dialog with VESC to control the speed motor via PPN signal (NO PWM)
Somebody have an idea ? or know how to do this ?
thx
Alain

[m5stack]

you could try search some keywords esp32 ppm `Arduino in Github. maybe some lib could do that.

https://github.com/search?q=arduino+ppm

[A Former User]

thx, found this https://github.com/schinken/PPMEncoder
try later

[A Former User]

Hi
no find yet a correct solution
somebody have exemple ?
other this need for me to return to my arduino board.
Thx

[m5stack]

maybe you could try their example:

https://github.com/kolod/Arduino-PPM-Generator

https://github.com/smilexth/Generate-PPM-Signal/blob/master/Generate-PPM-Signal.ino

[A Former User]

Hi
already test these program, no compatble with ESP32 or M5 stack seem a problem of timer.
turn on the loop.

type of error:
error: 'TCCR1A' was not declared in this scope

[m5stack]

@amn said in I would like to send a PPM with M5 stack Fire:

'TCCR1A' was not declared in this scope

'TCCR1A' was not declared in this scope

that looks like is a grammar error..... you just need define the function before you use it,

[A Former User]

@m5stack said in I would like to send a PPM with M5 stack Fire:
read on the web the timer is different between Arduino and ESP32
could be nice to find sample of code.
other this I'll continue my investigation
thx

[A Former User]

@amn
HI found this code: (how to adapt with potentiometre for the lenght of pulse , ?)

//////////////////////CONFIGURATION///////////////////////////////
#define chanel_number 1 //set the number of chanels
#define default_servo_value 1500 //set the default servo value
#define PPM_FrLen 22500 //set the PPM frame length in microseconds (1ms = 1000µs)
#define PPM_PulseLen 300 //set the pulse length
#define onState 1 //set polarity: 1 is positive, 0 is negative
#define sigPin 36 //set 10 PPM signal pin on the arduino

/this array holds the servo values for the ppm signal
change theese values in your code (usually servo values are between 1000 and 2000)/
int ppm[chanel_number];

void setup(){
// Initialize the M5Stack object
M5.begin();
/*
Power chip connected to gpio21, gpio22, I2C device
Set battery charging voltage and current
If used battery, please call this function in your project
*/
M5.Power.begin();

M5.Lcd.fillScreen(BLACK);
M5.Lcd.setTextColor(GREEN , BLACK);
M5.Lcd.setTextSize(2);

//initiallize default ppm values
for(int i=0; i<chanel_number; i++){
ppm[i]= default_servo_value;
}

pinMode(sigPin, OUTPUT);
digitalWrite(sigPin, !onState); //set the PPM signal pin to the default state (off)
}

void loop(){
//put main code here
ppmWrite();

}

void ppmWrite(){ //generate PPM signal
static unsigned long lastFrLen;
static unsigned long lastServo;
static unsigned long lastPulse;
static boolean PPM_run;
static boolean pulse;
static boolean pulseStart = true;
static byte counter;
static byte part = true;

if(micros() - lastFrLen >= PPM_FrLen){ //start PPM signal after PPM_FrLen has passed
lastFrLen = micros();
PPM_run = true;
}

if(counter >= chanel_number){
PPM_run = false;
counter = 0;
pulse = true; //put out the last pulse
}

if(PPM_run){
if (part){ //put out the pulse
pulse = true;
part = false;
lastServo = micros();
}
else{ //wait till servo signal time (values from the ppm array) has passed
if(micros() - lastServo >= ppm[counter]){
counter++; //do the next channel
part = true;
}
}
}

if(pulse){
if(pulseStart == true){ //start the pulse
digitalWrite(sigPin, onState);
pulseStart = false;
lastPulse = micros();
}
else{ //will wait till PPM_PulseLen has passed and finish the pulse
if(micros() - lastPulse >= PPM_PulseLen){
digitalWrite(sigPin, !onState);
pulse = false;
pulseStart = true;
}
}
}
}