Posted on May 20, 2015 at 20:15We have two different projects that I work on, both custom boards, one with an STM32F405xx and one with an STM32F427xx. I have a common code base that I'm using for both. However when I monitor VBAT via ADC the value I get back on the STM32F427xx board is half what I get on the STM32F405xx for the same input voltage due to the difference in the bridge divider. From the Ref manual:
''13.11 Battery charge monitoring</p>
The VBATE bit in the ADC_CCR register is used to switch to the battery voltage. As theV
BAT
voltage could be higher than V
DDA
, to ensure the correct operation of the ADC, theV
BAT
pin is internally connected to a bridge divider.
When the VBATE is set, the bridge is automatically enabled to connect:
- </p>
VBAT/2 to the ADC1_IN18 input channel, on STM32F40xx and STM32F41xx devices
</li>
- </p>
VBAT/4 to the ADC1_IN18 input channel, on STM32F42xx and STM32F43xx devices
'' </li></ul>
I use the CubeMX software to configure my projects. So my question is this: Is there a way either at compile time (via some &sharpdefine) or runtime to determine what the bridge divider is so I can do the necessary conversion without putting in my own &sharpdefine or similar?Thanks,Craig
#stm32f4-adc-vbat-bridge-divider
