H7 Fix frozen ADC values (#12439)

H7 ADC buffer invalidate cache
betaflight · Mar 3, 2023 · f59b7e7 · f59b7e7
1 parent ee77239
commit f59b7e7
Showing 1 changed file with 7 additions and 3 deletions.
diff --git a/src/main/drivers/stm32/adc_stm32h7xx.c b/src/main/drivers/stm32/adc_stm32h7xx.c
@@ -272,7 +272,12 @@ void adcInitCalibrationValues(void)
 // Need this separate from the main adcValue[] array, because channels are numbered
 // by ADC instance order that is different from ADC_xxx numbering.
 
-static volatile DMA_RAM uint16_t adcConversionBuffer[ADC_CHANNEL_COUNT] __attribute__((aligned(32)));
+#define ADC_BUF_LENGTH ADC_CHANNEL_COUNT
+#define ADC_BUF_BYTES (ADC_BUF_LENGTH * sizeof(uint16_t))
+#define ADC_BUF_CACHE_ALIGN_BYTES  ((ADC_BUF_BYTES + 0x20) & ~0x1f)
+#define ADC_BUF_CACHE_ALIGN_LENGTH (ADC_BUF_CACHE_ALIGN_BYTES / sizeof(uint16_t))
+
+static volatile DMA_RAM uint16_t adcConversionBuffer[ADC_BUF_CACHE_ALIGN_LENGTH] __attribute__((aligned(32)));
 
 void adcInit(const adcConfig_t *config)
 {
@@ -535,8 +540,7 @@ void adcInit(const adcConfig_t *config)
 void adcGetChannelValues(void)
 {
     // Transfer values in conversion buffer into adcValues[]
-    // Cache coherency should be maintained by MPU facility
-
+    SCB_InvalidateDCache_by_Addr((uint32_t*)adcConversionBuffer, ADC_BUF_CACHE_ALIGN_BYTES);
     for (int i = 0; i < ADC_CHANNEL_INTERNAL_FIRST_ID; i++) {
         if (adcOperatingConfig[i].enabled) {
             adcValues[adcOperatingConfig[i].dmaIndex] = adcConversionBuffer[adcOperatingConfig[i].dmaIndex];