working on silabs support

src/drivers/hardware_specific/silabs/silabs_mcu.cpp

@@ -19,18 +19,17 @@ void setupPWM(int pin_nr, long pwm_frequency, bool active_high, SilabsDriverPara
 	GPIO_Port_TypeDef port = getSilabsPortFromArduinoPin(pin_nr);
 	uint32_t pin = getSilabsPinFromArduinoPin(pin_nr);
 	TIMER_TypeDef* timer = TIMER0; // TODO determine correct timer
-	uint32_t timerFreq = 0;
-	uint32_t topValue = 0;
 	//CMU_ClockEnable(cmuClock_GPIO, true); assume this is done by Arduino core
 	CMU_ClockEnable(cmuClock_TIMER0, true); // enable timer clock
 
   	TIMER_Init_TypeDef timerInit = TIMER_INIT_DEFAULT;
 	timerInit.enable = false;
 	timerInit.mode = timerModeUpDown;
-	// TODO adjust pre-scaler as needed to get the desired frequency
 	uint32_t max = TIMER_MaxCount(timer);
-	timerFreq = CMU_ClockFreqGet(cmuClock_TIMER0) / (timerInit.prescale + 1);
-	topValue = (timerFreq / pwm_frequency);
+	timerInit.prescale = pwm_frequency / max;
+	// TODO adjust pre-scaler as needed to get the desired frequency
+	uint32_t timerFreq = CMU_ClockFreqGet(cmuClock_TIMER0) / (timerInit.prescale + 1);
+	uint32_t topValue = (timerFreq / pwm_frequency / 2);
 	TIMER_TopSet(timer, topValue);
 
   	TIMER_InitCC_TypeDef timerCCInit = TIMER_INITCC_DEFAULT;
@@ -41,6 +40,12 @@ void setupPWM(int pin_nr, long pwm_frequency, bool active_high, SilabsDriverPara
                     			 | (pin << _GPIO_TIMER_CC0ROUTE_PIN_SHIFT);
   	TIMER_InitCC(timer, 0, &timerCCInit);
 
+	params->timer[index] = timer;
+	params->channel[index] = 0;
+	params->pins[index] = pin_nr;
+	params->pwm_frequency = pwm_frequency;
+	params->resolution = topValue;
+
 	// TODO enable all the timers at the same time?
 	TIMER_Enable(timer, true);
 }

src/drivers/hardware_specific/silabs/silabs_mcu.h

@@ -1,3 +1,65 @@
+/**
+ * Silabs support for SimpleFOC library
+ * 
+ * The Silabs Gecko EFR32 procossors as used in the Arduino Nano Matter have the following
+ * features:
+ *  - 2 × 32-bit Timer/Counter with 3 Compare/Capture/PWM channels (TIMER0, TIMER1)
+ *  - 3 × 16-bit Timer/Counter with 3 Compare/Capture/PWM channels (TIMER2, TIMER3, TIMER4)
+ *  - All timers support dead-time insertion (DTI)
+ *  - Centre-aligned PWM mode
+ *  - Buffered compare register to ensure glitch-free update of compare values
+ *  - Timers can trigger ADC and DMA via reflex system
+ *  - Timers can be started/stopped synchronously by other timers
+ * 
+ * The MCU is very flexible regarding its pin assigments. The following is the possible
+ * assignments:
+ * 
+ *  GPIO port A: TIMER0, TIMER1, TIMER2, TIMER4
+ *  GPIO port B: TIMER0, TIMER1, TIMER2, TIMER4
+ *  GPIO port C: TIMER0, TIMER1, TIMER3
+ *  GPIO port D: TIMER0, TIMER1, TIMER3
+ *  
+ * Any pin of these ports can be used with any of the 3 channels or the inverted 
+ * channels of the possible timers.
+ * 
+ * This suggests the following usage paradigm:
+ *  - 3-PWM or 6-PWM use a single timer, all 3 channels
+ *  - 2-PWM uses two channels of a single timer
+ *  - 1-PWM uses a single channel
+ *  - 4-PWM uses two timers, two channels each (we could try to sync them)
+ *  - TIMER0 and TIMER1 are preferred, since they can be used with all GPIO ports
+ * 
+ * Nano Matter Pin/Port assignments:
+ *  D0 TX: PA04
+ *  D1 RX: PA05
+ *  D3: PC06
+ *  D4 SDA1: PC07
+ *  D5 SCL1: PC08
+ *  D6: PC09
+ *  D7: PD02
+ *  D8: PD03
+ *  D9: PTI_DATA: PD04
+ *  D10 SS PTI_SYNC: PD05
+ *  D11 MOSI: PA09
+ *  D12 MISO: PA08
+ *  D13 CLK: PB04
+ *  A0: PB00
+ *  A1: PB02
+ *  A2: PB05
+ *  A3: PC00
+ *  A4 SDA: PA06
+ *  A5 SCL: PA07
+ *  A6: PB01
+ *  A7: PB03
+ *  RGB_R: PC01
+ *  RGB_G: PC02
+ *  RGB_B: PC03
+ * 
+ * So the Nano Matter could use any of TIMER0, TIMER1, or TIMER3 with 
+ * the SimpleFOC Nano Shield (3-PWM mode).
+ * 
+ */
+
 
 #pragma once
 
@@ -12,7 +74,8 @@ typedef struct SilabsDriverParams {
     int pins[6];
     TIMER_TypeDef* timer[6];
     uint8_t channel[6];
-    long pwm_frequency;
+    uint32_t pwm_frequency;
+    uint32_t resolution;
     float dead_zone;
 };