Stm32f407 DIsovery ADC Issue

[ffaisaldj]

Posted on October 16, 2013 at 15:00

Hi,

I have a relay circuit which has fourteen relay output (i.e 14 devices can be switched on or off from this) , I have attached the circuit for a single output.

I am sending command to switch on the related output through the GPIO of a STM32 f4 discovery  board .

I am reading 14 channels of ADC1 in scan mode with multi channel configuration to get the power consumption through each output

I am Using following ADC pins for getting the data.

PA0

PA1

PA2

PA3

PA4

PA5

PA7

PB0

PB1

PC0

PC1

PC2

PC4

PC5

My first problem is that I am constantly getting value on PC0 (even though there is no load) because it is internally connected to the temerature sensor..How Can I disable this connection of internal temperature sensor so that I can use this pin as a channel of ADC.

Second problem is that at PA5 and PA7 I am also getting the voltage level without applying any load...

I have detached my board with discovery and check the pins individually and I saw that PA5 and PA7 are producing constantly around 2.5 Volt ...why..

with regards,

Muhammad Faisal.

 

#stm32f4-disovery

[Tesla DeLorean]

Posted on October 16, 2013 at 15:36

The manual for the STM32F4-Discovery would illustrate why pins wouldn't be useable. PA5,6,7 are attached to the LIS302DL

You'd have to remove parts or cuts traces to free up the pins. That or buy a break-out board that is free of all this other circuitry.