Merge pull request #8103 from jeromecoutant/PR_L0_ADC

STM32 L0 ADC internal channel fix

Author: 0xc0170

targets/TARGET_STM/TARGET_STM32L0/TARGET_STM32L072xZ/TARGET_DISCO_L072CZ_LRWAN1/PeripheralPins.c

@@ -70,9 +70,8 @@ MBED_WEAK const PinMap PinMap_ADC[] = {
 };
 
 MBED_WEAK const PinMap PinMap_ADC_Internal[] = {
-    {ADC_TEMP,   ADC_1,    STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 17, 0)},
-    {ADC_VREF,   ADC_1,    STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0,  0, 0)},
-    {ADC_VBAT,   ADC_1,    STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 18, 0)},
+    {ADC_VREF,   ADC_1,    STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 17, 0)}, // ADC_IN17 // VREFINT
+    {ADC_TEMP,   ADC_1,    STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 18, 0)}, // ADC_IN18 // VSENSE
     {NC, NC, 0}
 };
 

targets/TARGET_STM/TARGET_STM32L0/TARGET_STM32L0x2xZ/TARGET_MTB_MURATA_ABZ/PeripheralPins.c

@@ -48,9 +48,8 @@ const PinMap PinMap_ADC[] = {
 };
 
 const PinMap PinMap_ADC_Internal[] = {
-    {ADC_TEMP, ADC_1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 17, 0)}, // Internal channel
-    {ADC_VREF, ADC_1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0,  0, 0)}, // Internal channel
-    {ADC_VBAT, ADC_1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 18, 0)}, // Internal channel
+    {ADC_VREF,   ADC_1,    STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 17, 0)}, // ADC_IN17 // VREFINT
+    {ADC_TEMP,   ADC_1,    STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 18, 0)}, // ADC_IN18 // VSENSE
     {NC,       NC,    0}
 };
 

targets/TARGET_STM/TARGET_STM32L0/analogin_device.c

@@ -172,6 +172,12 @@ uint16_t adc_read(analogin_t *obj)
 
     HAL_ADC_ConfigChannel(&obj->handle, &sConfig);
 
+    /* need to wait for some stabilization time after setting the TSEN bit in the ADC_CCR
+    register to wake up the temperature sensor from power down mode */
+    if (sConfig.Channel == ADC_CHANNEL_TEMPSENSOR) {
+        wait_ms(20);
+    }
+
     HAL_ADC_Start(&obj->handle); // Start conversion
 
     // Wait end of conversion and get value