Fix bug sandeepmistry#169

wiring_analog_* : fallback to digitalWrite if no available PWM channel (copied from AVR core)
wiring_analog_nRF52.c : convert pwmChannelPins & pwmChannelSequence -> pwmContext to semi-standardise pwm pin allocation and pwm status between nRF51 and nRF52
wiring_private.h : Move pwm structures defines out of wiring_analog_* into wiring_private and make the instantiation of these structure externs instead of statics
wiring_digital.c : disable the appropriate pwm timer when a digitalWrite is sent to an allocated (from analogWrite) pwm pin, and free up the pwm channel for re-allocation

Author: micooke

cores/nRF5/wiring_analog_nRF51.c

@@ -28,27 +28,16 @@
 extern "C" {
 #endif
 
-#define PWM_COUNT 3
-#define PIN_FREE 0xffffffff
-
-struct PWMContext {
-  uint32_t pin;
-  uint32_t value;
-  uint32_t channel;
-  uint32_t mask;
-  uint32_t event;
-};
+static uint32_t adcReference = ADC_CONFIG_REFSEL_SupplyOneThirdPrescaling;
+static uint32_t adcPrescaling = ADC_CONFIG_INPSEL_AnalogInputOneThirdPrescaling;
 
-static struct PWMContext pwmContext[PWM_COUNT] = {
+struct PWMContext pwmContext[PWM_COUNT] = {
   { PIN_FREE, 0, 1, TIMER_INTENSET_COMPARE1_Msk, 1 },
   { PIN_FREE, 0, 2, TIMER_INTENSET_COMPARE2_Msk, 2 },
   { PIN_FREE, 0, 3, TIMER_INTENSET_COMPARE3_Msk, 3 }
 };
 
-static int timerEnabled = 0;
-
-static uint32_t adcReference = ADC_CONFIG_REFSEL_SupplyOneThirdPrescaling;
-static uint32_t adcPrescaling = ADC_CONFIG_INPSEL_AnalogInputOneThirdPrescaling;
+struct PWMStatus pwmStatus[PWM_TIMER_COUNT] = {0, TIMER1_IRQn};
 
 static uint32_t readResolution = 10;
 static uint32_t writeResolution = 8;
@@ -229,7 +218,7 @@ void analogWrite( uint32_t ulPin, uint32_t ulValue )
 
   ulPin = g_ADigitalPinMap[ulPin];
 
-  if (!timerEnabled) {
+  if (pwmStatus[0].numActive == 0) {
     NVIC_SetPriority(TIMER1_IRQn, 3);
     NVIC_ClearPendingIRQ(TIMER1_IRQn);
     NVIC_EnableIRQ(TIMER1_IRQn);
@@ -245,8 +234,6 @@ void analogWrite( uint32_t ulPin, uint32_t ulValue )
     NRF_TIMER1->INTENSET = TIMER_INTENSET_COMPARE0_Msk;
 
     NRF_TIMER1->TASKS_START = 0x1UL;
-
-    timerEnabled = true;
   }
 
   for (int i = 0; i < PWM_COUNT; i++) {
@@ -259,17 +246,25 @@ void analogWrite( uint32_t ulPin, uint32_t ulValue )
                                | ((uint32_t)GPIO_PIN_CNF_DRIVE_S0S1       << GPIO_PIN_CNF_DRIVE_Pos)
                                | ((uint32_t)GPIO_PIN_CNF_SENSE_Disabled   << GPIO_PIN_CNF_SENSE_Pos);
 
-      ulValue = mapResolution(ulValue, writeResolution, 8);
-
       pwmContext[i].value = ulValue;
 
       NRF_TIMER1->CC[pwmContext[i].channel] = ulValue;
 
       NRF_TIMER1->INTENSET = pwmContext[i].mask;
-
-      break;
+      pwmStatus[0].numActive++;
+      return;
     }
   }
+
+  // fallback to digitalWrite if no available PWM channel
+  if (ulValue < 128)
+  {
+    digitalWrite(ulPin, LOW);
+  }
+  else
+  {
+    digitalWrite(ulPin, LOW);
+  }
 }
 
 void TIMER1_IRQHandler(void)

cores/nRF5/wiring_analog_nRF52.c

@@ -31,20 +31,19 @@ extern "C" {
 static uint32_t saadcReference = SAADC_CH_CONFIG_REFSEL_Internal;
 static uint32_t saadcGain      = SAADC_CH_CONFIG_GAIN_Gain1_5;
 
-#define PWM_COUNT 3
-
-static NRF_PWM_Type* pwms[PWM_COUNT] = {
+NRF_PWM_Type* pwms[PWM_COUNT] = {
   NRF_PWM0,
   NRF_PWM1,
   NRF_PWM2
 };
 
-static uint32_t pwmChannelPins[PWM_COUNT] = {
-  0xFFFFFFFF,
-  0xFFFFFFFF,
-  0xFFFFFFFF
+struct PWMContext pwmContext[PWM_COUNT] = {
+  { PIN_FREE, 0 },
+  { PIN_FREE, 0 },
+  { PIN_FREE, 0 }
 };
-static uint16_t pwmChannelSequence[PWM_COUNT];
+
+struct PWMStatus pwmStatus[PWM_TIMER_COUNT] = {0, 0};
 
 static int readResolution = 10;
 static int writeResolution = 8;
@@ -220,9 +219,9 @@ void analogWrite( uint32_t ulPin, uint32_t ulValue )
   ulPin = g_ADigitalPinMap[ulPin];
 
   for (int i = 0; i < PWM_COUNT; i++) {
-    if (pwmChannelPins[i] == 0xFFFFFFFF || pwmChannelPins[i] == ulPin) {
-      pwmChannelPins[i] = ulPin;
-      pwmChannelSequence[i] = ulValue | bit(15);
+    if (pwmContext[i].pin == PIN_FREE || pwmContext[i].pin == ulPin) {
+      pwmContext[i].pin = ulPin;
+      pwmContext[i].value = ulValue | bit(15);
 
       NRF_PWM_Type* pwm = pwms[i];
 
@@ -236,15 +235,25 @@ void analogWrite( uint32_t ulPin, uint32_t ulValue )
       pwm->COUNTERTOP = (1 << writeResolution) - 1;
       pwm->LOOP = 0;
       pwm->DECODER = ((uint32_t)PWM_DECODER_LOAD_Common << PWM_DECODER_LOAD_Pos) | ((uint32_t)PWM_DECODER_MODE_RefreshCount << PWM_DECODER_MODE_Pos);
-      pwm->SEQ[0].PTR = (uint32_t)&pwmChannelSequence[i];
+      pwm->SEQ[0].PTR = (uint32_t)&(pwmContext[i].value);
       pwm->SEQ[0].CNT = 1;
       pwm->SEQ[0].REFRESH  = 1;
       pwm->SEQ[0].ENDDELAY = 0;
       pwm->TASKS_SEQSTART[0] = 0x1UL;
-
-      break;
+      pwmStatus[0].numActive++;
+      return;
     }
   }
+
+  // fallback to digitalWrite if no available PWM channel
+  if (ulValue < 128)
+  {
+    digitalWrite(ulPin, LOW);
+  }
+  else
+  {
+    digitalWrite(ulPin, LOW);
+  }
 }
 
 #ifdef __cplusplus

cores/nRF5/wiring_digital.c

@@ -20,6 +20,13 @@
 #include "nrf.h"
 
 #include "Arduino.h"
+#include "wiring_private.h"
+
+extern struct PWMContext pwmContext[PWM_COUNT];
+extern struct PWMStatus pwmStatus[PWM_TIMER_COUNT];
+#ifdef NRF52
+extern NRF_PWM_Type* pwms[PWM_COUNT];
+#endif
 
 #ifdef __cplusplus
 extern "C" {
@@ -86,18 +93,42 @@ void digitalWrite( uint32_t ulPin, uint32_t ulVal )
 
   ulPin = g_ADigitalPinMap[ulPin];
 
+  for (uint8_t i = 0; i < PWM_COUNT; i++)
+  {
+    if (pwmContext[i].pin == ulPin)
+    {
+      pwmContext[i].pin = PIN_FREE;
+      #ifdef NRF52
+      // Disable the PWM
+      NRF_PWM_Type* pwm = pwms[i];
+      pwm->ENABLE = (PWM_ENABLE_ENABLE_Disabled << PWM_ENABLE_ENABLE_Pos);
+      #endif
+      pwmStatus[0].numActive--;
+    }
+  }
+
+  #ifdef NRF51
+  // Turn off the Timer if no pwm signals are allocated
+  for (uint8_t i = 0; i < PWM_TIMER_COUNT; i++)
+  {
+   if (pwmStatus[i].numActive == 0)
+    {
+      NVIC_ClearPendingIRQ(pwmStatus[i].irqNumber);
+      NVIC_DisableIRQ(pwmStatus[i].irqNumber);
+    }
+  }
+  #endif
+
   switch ( ulVal )
   {
     case LOW:
       NRF_GPIO->OUTCLR = (1UL << ulPin);
-    break ;
+      break;
 
     default:
       NRF_GPIO->OUTSET = (1UL << ulPin);
-    break ;
+      break;
   }
-
-  return ;
 }
 
 int digitalRead( uint32_t ulPin )

cores/nRF5/wiring_private.h

@@ -26,9 +26,26 @@
 extern "C" {
 #endif
 
-
 #include "wiring_constants.h"
 
+#define PWM_COUNT 3
+#define PWM_TIMER_COUNT 1 // 3 channels of TIMER1 are used. TIMER2 also could be used for PWM
+#define PIN_FREE 0xffffffff
+
+struct PWMContext {
+  uint32_t pin;
+  uint32_t value;
+  #ifdef NRF51
+  uint32_t channel;
+  uint32_t mask;
+  uint32_t event;
+  #endif
+};
+
+struct PWMStatus {
+  int8_t numActive;
+  int8_t irqNumber;
+};
 
 #ifdef __cplusplus
 } // extern "C"