Added support for Adafruit QtPy M0 board.

README.md

@@ -28,14 +28,15 @@ Set input clock divider and Turbo Mode (which uses a 96MHz instead of a 48Mhz in
 
 ```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):**
+**Initialize 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.
+* For the Arduino Nano 33 IoT, you need to initialize 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 initialize 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 initialize 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 initialize timer 0 for pins 0 and 2, and timer 1 for pins 3 and 4.
+* For the Adafruit QtPy M0, you need to initialize timer 0 for pins 2, 3, 8, and 10. Timer 1 for pins 6, 7, and 9.  Timer 2 for pins 4 and 5.  **Note** that pins 7 & 9 share a capture and compare buffer (CCB1) so you can't get different PWM duty cycles from them at the same time.  
 
 MaxSteps is 0xFFFFFF for (24-bits) timers 0 and 1, and 0xFFFF for (16 bits) timer 2.
 

src/SAMD21turboPWM.h

@@ -116,6 +116,21 @@ static const PinLookup pinTable[] = {
 { 4, PORTA,  6, 1, &REG_TCC1_CCB0, PORT_PMUX_PMUXE_E}
 //Table end
 
+#elif defined (ADAFRUIT_QTPY_M0)
+//Table begin
+{-1, 0, 0, 0, 0, 0},
+{-1, 0, 0, 0, 0, 0},
+{ 2, PORTA,  4, 0, &REG_TCC0_CCB0, PORT_PMUX_PMUXE_E},
+{ 3, PORTA,  5, 0, &REG_TCC0_CCB1, PORT_PMUX_PMUXO_E},
+{ 4, PORTA, 16, 2, &REG_TCC2_CCB0, PORT_PMUX_PMUXE_E},
+{ 5, PORTA, 17, 2, &REG_TCC2_CCB1, PORT_PMUX_PMUXO_E},
+{ 6, PORTA,  6, 1, &REG_TCC1_CCB0, PORT_PMUX_PMUXE_E},
+{ 7, PORTA,  7, 1, &REG_TCC1_CCB1, PORT_PMUX_PMUXO_E},
+{ 8, PORTA, 11, 0, &REG_TCC0_CCB3, PORT_PMUX_PMUXO_F},  // alt timer
+{ 9, PORTA,  9, 1, &REG_TCC1_CCB1, PORT_PMUX_PMUXO_F},  // alt timer
+{10, PORTA, 10, 0, &REG_TCC0_CCB2, PORT_PMUX_PMUXE_F}   // alt timer
+//Table end
+
 #else
   #error Board not supported by Turbo PWM Library
 #endif