Using 8 pins as pwm output

Official Hardware UNO Family UNO R4 WiFi
1

The Arduino Uno R4 is equipped with the R7FA4M1AB3CFM processor. According to the schematics of the Arduino R4 WiFi, all digital pins are capable of hardware-based PWM. However, the Arduino API does not currently support the initiation of 8 different PWM signals, each with a unique duty cycle. Despite this, the chip's hardware manual includes an example demonstrating that it is indeed possible.

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I have gone through the PWM and FspTimer files, but I don’t have enough experience to make this work.

Does anyone know how to get this working? My end goal is to control 8 individual LEDs with different duty cycles.

2

Why not just use PCA9685 or TLC5940? Or even smart LEDs like WS2812 or PL9823 for example.

4

Thank you for your response.

I tried your solution, and it works. Using analogWrite, you can write to both Channel A and Channel B of a timer. So I can work with this solloution!

Interestingly, the following example code using pwm.h works only when you use either Channel A or Channel B, but not both at the same time.

#include "pwm.h"

PwmOut pwm1(D2);
PwmOut pwm2(D5);

void setup() {

  pwm1.begin(20000.0f, 0.0f);
  pwm2.begin(20000.0f, 0.0f);

  pwm1.pulse_perc(100.0f);
  pwm2.pulse_perc(100.0f);
}

void loop(){}

When you change D5 to D3, the processor crashes.
I think it because you set twice the frequency of the timer.

5

I realize this is an old post, but it came up when I ran into the same issue.

I had to make a modified version of the pwm.h lib that makes one instance of the FspTimer per hardware timer used. I was then able to add the second channel (A/B) to an existing timer by stopping it, enabling the new PWM chan, and restarting it. My code looks something like this:

if (_timer->is_opened()) {
    _timer->stop();
    _timer->close();
}

auto pin_cgf = getPinCfgs(_pin, PIN_CFG_REQ_PWM);
_pwmChan = IS_PWM_ON_A(pin_cgf[0]) ? CHANNEL_A : CHANNEL_B;
_timer->enable_pwm_channel(_pwmChan); //enable correct output channel A/B

//configure pin for GPT peripheral
R_IOPORT_PinCfg(&g_ioport_ctrl, g_pin_cfg[_pin].pin, IOPORT_CFG_PERIPHERAL_PIN | IOPORT_PERIPHERAL_GPT1);

_timer->open();
_timer->start();

There might be a better way, but this worked for me.