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| author | blmorris <bryan.morrissey@gmail.com> | 2015-02-06 13:56:27 -0500 |
|---|---|---|
| committer | blmorris <bryan.morrissey@gmail.com> | 2015-02-06 13:56:27 -0500 |
| commit | 97f14606f528180d1482cffbe3571163a1dd9273 (patch) | |
| tree | 349758f1eb082ad342d1473c0034eb05ff237ff3 | |
| parent | 8775caf9f1c97ecc64f22e355b670ba74d5bd098 (diff) | |
| download | micropython-97f14606f528180d1482cffbe3571163a1dd9273.tar.gz micropython-97f14606f528180d1482cffbe3571163a1dd9273.zip | |
stmhal/adc.c: Fix calculation of read_core_vref()
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
| -rw-r--r-- | stmhal/adc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/stmhal/adc.c b/stmhal/adc.c index cacfed7a8a..4e0ec46a9a 100644 --- a/stmhal/adc.c +++ b/stmhal/adc.c @@ -363,7 +363,7 @@ float adc_read_core_vref(ADC_HandleTypeDef *adcHandle) { // be 12-bits. raw_value <<= (12 - adc_get_resolution(adcHandle)); - return raw_value * VBAT_DIV / 4096.0f * 3.3f; + return raw_value / 4096.0f * 3.3f; } #endif |