stm32/machine_adc: Enable ADC re-read errata handling for STM32WB55.

pi-anl · dpgeorge · commit 17898f8607dc · 2025-06-04T02:11:23.000+10:00
Signed-off-by: Andrew Leech &lt;andrew.leech@planetinnovation.com.au&gt;
diff --git a/ports/stm32/machine_adc.c b/ports/stm32/machine_adc.c
@@ -445,10 +445,13 @@ static void adc_config_channel(ADC_TypeDef *adc, uint32_t channel, uint32_t samp
 
 static uint32_t adc_read_channel(ADC_TypeDef *adc) {
     uint32_t value;
-    #if defined(STM32G4)
-    // For STM32G4 there is errata 2.7.7, "Wrong ADC result if conversion done late after
-    // calibration or previous conversion".  According to the errata, this can be avoided
-    // by performing two consecutive ADC conversions and keeping the second result.
+    #if defined(STM32G4) || defined(STM32WB)
+    // For STM32G4 errata 2.7.7 / STM32WB errata 2.7.1:
+    // "Wrong ADC result if conversion done late after calibration or previous conversion"
+    // states an incorrect reading is returned if more than 1ms has elapsed since the last
+    // reading or calibration. According to the errata, this can be avoided by performing
+    // two consecutive ADC conversions and keeping the second result.
+    // Note: On STM32WB55 @ 64Mhz each ADC read takes ~ 3us.
     for (uint8_t i = 0; i < 2; i++)
     #endif
     {
