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stmhal/adc.c: Fix calculation of read_core_vref()

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There was a stray factor of 2 (VBAT_DIV) that looks like it was copied incorrectly from the read_core_vbat() function.
The factor exists in read_core_vbat() because VBAT is measured through a 2:1 voltage divider.
read_core_vref now returns values around 1.21V (assuming that external reference voltage is 3.3V) which is in line with the datasheet values.
See comment at http://forum.micropython.org/viewtopic.php?f=6&t=533&p=2991#p2991
This commit is contained in:
blmorris 2015-02-06 13:56:27 -05:00
parent 8775caf9f1
commit 97f14606f5
1 changed files with 1 additions and 1 deletions
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stmhal/adc.c
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@ -363,7 +363,7 @@ float adc_read_core_vref(ADC_HandleTypeDef *adcHandle) {
// be 12-bits. // be 12-bits.
raw_value <<= (12 - adc_get_resolution(adcHandle)); raw_value <<= (12 - adc_get_resolution(adcHandle));
return raw_value * VBAT_DIV / 4096.0f * 3.3f; return raw_value / 4096.0f * 3.3f;
} }
#endif #endif