stm32/machine_adc: Handle ADC resolution less than 8 bits on all MCUs.

dpgeorge · dpgeorge · commit f7f8332ddf87 · 2023-06-15T11:02:55.000+10:00
All MCUs can have 6-bit resolution; see adc_cr_to_bits_table.

Signed-off-by: Damien George &lt;damien@micropython.org&gt;
diff --git a/ports/stm32/machine_adc.c b/ports/stm32/machine_adc.c
@@ -374,12 +374,10 @@ uint32_t adc_config_and_read_u16(ADC_TypeDef *adc, uint32_t channel, uint32_t sa
 
     // Scale raw reading to 16 bit value using a Taylor expansion (for bits <= 16).
     uint32_t bits = adc_get_bits(adc);
-    #if defined(STM32H7)
     if (bits < 8) {
         // For 6 and 7 bits
         return raw << (16 - bits) | raw << (16 - 2 * bits) | raw >> (3 * bits - 16);
     }
-    #endif
     return raw << (16 - bits) | raw >> (2 * bits - 16);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -374,12 +374,10 @@ uint32_t adc_config_and_read_u16(ADC_TypeDef *adc, uint32_t channel, uint32_t sa`
`374`	`374`
`375`	`375`	`// Scale raw reading to 16 bit value using a Taylor expansion (for bits <= 16).`
`376`	`376`	`uint32_t bits = adc_get_bits(adc);`
`377`		`- #if defined(STM32H7)`
`378`	`377`	`if (bits < 8) {`
`379`	`378`	`// For 6 and 7 bits`
`380`	`379`	`return raw << (16 - bits) \| raw << (16 - 2 * bits) \| raw >> (3 * bits - 16);`
`381`	`380`	`}`
`382`		`- #endif`
`383`	`381`	`return raw << (16 - bits) \| raw >> (2 * bits - 16);`
`384`	`382`	`}`
`385`	`383`