Note: Tested on the Arduino Nano 33 IoT, Adafruit Itsy Bitsy M0, and the Adafruit Trinket M0; untested on the Arduino Zero, the Arduino MKR series, and the Adafruit Feather M0, but should work. Let me know about problems.
Uses the SAMD21's timers TCC0, TCC1, and TCC2 to generate PWM signals on eight pins (four on the Adafruit Trinket M0):
- Nano 33 IoT: 4, 5, 6, 7, 8, 11, 12, and 13;
- Arduino Zero (untested), Adafruit Feather M0 (untested), Adafruit Itsy Bitsy M0: 3, 4, 8, 9, 10, 11, 12, and 13;
- MKR series (untested): 2, 3, 4, 5, 6, 7, 8, and 9;
- Adafruit Trinket M0: 0, 2, 3 and 4.
... Martin L. and Shawn Hymel for important parts of the code, and for explaining esoteric and dark stuff.
Allowed values in square brackets.
Include the library:
#include <SAMD21turboPWM.h>
Create a TurboPWM object (called pwm here, but name as you wish):
TurboPWM pwm;
Set input clock divider and Turbo Mode (which uses a 96MHz instead of a 48Mhz input clock):
pwm.setClockDivider([1-255], [true, false]);
Initialise timer x, with prescaler, with steps (resolution), with fast aka single-slope PWM (or not -> double-slope PWM):
pwm.timer([0, 1, 2], [1, 2, 4, 8, 16, 64, 256, 1024], [2-MaxSteps], [true, false]);
- For the Arduino Nano 33 IoT, you need to initialise timer 1 for pins 4 and 7, timer 0 for pins 5, 6, 8, and 12, and timer 2 for pins 11 and 13;
- For the Arduino Zero (untested), Adafruit Feather M0 (untested), and Adafruit Itsy Bitsy M0 you need to initialise timer 0 for pins 3, 4, 10 and 12, timer 1 for pins 8 and 9, and timer 2 for pins 11 and 13;
- For the Arduino MKR series (untested), you need to initialise timer 1 for pins 2 and 3, timer 0 for pins 4, 5, 6 and 7, and timer 2 for pins 8 and 9;
- For the Adafruit Trinket M0, you need to initialise timer 0 for pins 0 and 2, and timer 1 for pins 3 and 4.
MaxSteps is 0xFFFFFF for (24-bits) timers 0 and 1, and 0xFFFF for (16 bits) timer 2.
Start PWM on a pin with a duty cycle:
pwm.analogWrite([pin number], [0-1000]);
Enable/disable a timer:
pwm.enable([0, 1, 2], [true, false]);
Get a timer's current PWM frequency:
pwm.frequency([0, 1, 2]);
Also see the header file and the examples.
If you feel like donating for this library, you can do so here: http:https://ocrdu.nl/donations .