FEAT ADC-DMA fix deadlock

Author: maxlem

src/current_sense/LowSideCurrentSense.cpp

@@ -55,10 +55,13 @@ PhaseCurrent_s LowSideCurrentSense::getPhaseCurrents(){
     // current.b = (_readADCVoltage(pinB) - offset_ib)*gain_b;// amps
     // current.c = (!_isset(pinC)) ? 0 : (_readADCVoltage(pinC) - offset_ic)*gain_c; // amps
 
-    adc.readResults(current.a, current.b, current.c);
+    if(adc.readResults(current.a, current.b, current.c))
+    {
+        oldCurrent = current;
+    }
     adc.startADCScan();
 
-    return current;
+    return oldCurrent;
 }
 // Function synchronizing current sense with motor driver.
 // for in-line sensig no such thing is necessary

src/current_sense/LowSideCurrentSense.h

@@ -52,7 +52,8 @@ class LowSideCurrentSense: public CurrentSense{
     double offset_ia; //!< zero current A voltage value (center of the adc reading)
     double offset_ib; //!< zero current B voltage value (center of the adc reading)
     double offset_ic; //!< zero current C voltage value (center of the adc reading)
-
+  
+    PhaseCurrent_s oldCurrent;
     SAMDCurrentSenseADCDMA adc;
 
 };

src/current_sense/hardware_specific/samd21_mcu.cpp

@@ -40,17 +40,19 @@ void SAMDCurrentSenseADCDMA::startADCScan(){
   adcStartWithDMA();
 }
 
-void SAMDCurrentSenseADCDMA::readResults(float & a, float & b, float & c){
-  while(ADC->CTRLA.bit.ENABLE) ;
+bool SAMDCurrentSenseADCDMA::readResults(float & a, float & b, float & c){
+  if(ADC->CTRLA.bit.ENABLE)
+    return false;
   uint32_t ainA = g_APinDescription[pinA].ulADCChannelNumber;
   uint32_t ainB = g_APinDescription[pinB].ulADCChannelNumber;
-  uint32_t ainC = g_APinDescription[pinC].ulADCChannelNumber;
   a = adcBuffer[ainA] * countsToVolts;
   b = adcBuffer[ainB] * countsToVolts;
   if(_isset(pinC))
   {
+    uint32_t ainC = g_APinDescription[pinC].ulADCChannelNumber;
     c = adcBuffer[ainC] * countsToVolts;
   }
+  return true;
 }
 
 void SAMDCurrentSenseADCDMA::initPins(){
@@ -61,11 +63,11 @@ void SAMDCurrentSenseADCDMA::initPins(){
 
   uint32_t ainA = g_APinDescription[pinA].ulADCChannelNumber;
   uint32_t ainB = g_APinDescription[pinB].ulADCChannelNumber;
-  uint32_t ainC = g_APinDescription[pinC].ulADCChannelNumber;
   firstAIN = min(ainA, ainB);
   lastAIN = max(ainA, ainB);
   if( _isset(pinC) ) 
   {
+    uint32_t ainC = g_APinDescription[pinC].ulADCChannelNumber;
     pinMode(pinC, INPUT);
     firstAIN = min(firstAIN, ainC);
     lastAIN = max(lastAIN, ainC);
@@ -158,7 +160,7 @@ void SAMDCurrentSenseADCDMA::initDMA() {
 }
 
 
-void SAMDCurrentSenseADCDMA::adcToDMATransfer(void *rxdata,  size_t hwords) {
+void SAMDCurrentSenseADCDMA::adcToDMATransfer(void *rxdata,  uint32_t hwords) {
 
   DMAC->CHID.reg = DMAC_CHID_ID(channelDMA);
   DMAC->CHCTRLA.reg &= ~DMAC_CHCTRLA_ENABLE;
@@ -183,13 +185,19 @@ void SAMDCurrentSenseADCDMA::adcToDMATransfer(void *rxdata,  size_t hwords) {
 
 
 void adcStopWithDMA(void){
+  ADCsync();
   ADC->CTRLA.bit.ENABLE = 0x00;
+  
 }
 
 void adcStartWithDMA(void){
+  ADCsync();
   ADC->INPUTCTRL.bit.INPUTOFFSET = 0;
+  ADCsync();
   ADC->SWTRIG.bit.FLUSH = 1;
+  ADCsync();
   ADC->CTRLA.bit.ENABLE = 0x01; 
+  ADCsync();
 }
 
 void DMAC_Handler() {

src/current_sense/hardware_specific/samd21_mcu.h

@@ -1,6 +1,6 @@
 
 #include "../hardware_api.h"
-
+#include <stdint.h>
   typedef struct {
     uint16_t btctrl;
     uint16_t btcnt;
@@ -18,11 +18,11 @@ class SAMDCurrentSenseADCDMA
 
   void init();
   void startADCScan();
-  void readResults(float & a, float & b, float & c);
+  bool readResults(float & a, float & b, float & c);
 
 private:
 
-  void adcToDMATransfer(void *rxdata,  size_t hwords);
+  void adcToDMATransfer(void *rxdata,  uint32_t hwords);
 
   void initPins();
   void initADC();