Read GPIO Analog

[NASI]

Hello,

I set one of GPIO to Analog mode and I want to read its value, by using HAL library.

Should I just use HAL_GPIO_ReadPin to read the value?

Thank you.

[gbm]

In analog mode, the digital input circuit is turned off and the input value reads as 0 regardless of the voltage.

[NASI]

Thank you gbm

I am using STM32F105, and I connect an analog signal to PB10. In this case I want to monitor analog value. So base on you answer, I get 0 all time?

[TDK]

HAL_GPIO_ReadPin reads IDR which is disconnected in analog mode. You need to set the pin to input mode, or use the ADC to read the value.

[NASI]

Thank you TDK

there is no ADC mode for PB10

so I have to use GPIO_input mode?

[TDK]

Yes, so it can only read a digital value (0 or 1) rather than an analog value.

[ENGIN TANRIKULU]

This pin does not allow ADC reading, but why is there an option called GPIO Analog?

[AScha.3]

The GPIO analogue option is not to be confused with an ADC input, but in principle has two functions:

• Disconnecting the external pin from the digital function. This is useful, for example, to disconnect the Schmitt trigger present at the digital input from a floating input, because this can lead to high-frequency switching of this trigger with associated current consumption.
• Connecting any analogue peripherals (e.g. opamp, comparator, ADC) that may be present, but do not necessarily have to be in the respective case.

from

https://community.st.com/t5/stm32-mcus-products/use-gpio-analog-for-adc-read-value-on-stm32h735/td-p/75324

 

[NASI]

Just want to be sure that there is no way to read analog value (not digital value) from PB10 ?

[TDK]

You can only read analog values from pins connected to the ADC. PB10 isn’t one of those.

[NASI]

Thank you @TDK​