STM32F2 ADC internal channels update

Author: jeromecoutant

targets/TARGET_STM/TARGET_STM32F2/analogin_device.c

@@ -107,7 +107,7 @@ uint16_t adc_read(analogin_t *obj)
 
     // Configure ADC channel
     sConfig.Rank         = 1;
-    sConfig.SamplingTime = ADC_SAMPLETIME_15CYCLES;
+    sConfig.SamplingTime = ADC_SAMPLETIME_56CYCLES;
     sConfig.Offset       = 0;
 
     switch (obj->channel) {
@@ -161,12 +161,15 @@ uint16_t adc_read(analogin_t *obj)
             break;
         case 16:
             sConfig.Channel = ADC_CHANNEL_TEMPSENSOR;
+            sConfig.SamplingTime = ADC_SAMPLETIME_480CYCLES;
             break;
         case 17:
             sConfig.Channel = ADC_CHANNEL_VREFINT;
+            sConfig.SamplingTime = ADC_SAMPLETIME_480CYCLES;
             break;
         case 18:
             sConfig.Channel = ADC_CHANNEL_VBAT;
+            sConfig.SamplingTime = ADC_SAMPLETIME_480CYCLES;
             break;
         default:
             return 0;