MPC5644A -ADC

[bulent_kupeli]

Hello, I am using MPC5644A microcontroller with 20 MHz and 40 MHz crystals. When I used 20 MHz with the MPC5644A, I read the some values ​​from the ADC channel but when I use the 40 MHz crystal with same code, I cannot read any value from the ADC channels, I checked my power and ADC signals and did not see any problems. I checked the pins of the MPC5644A but did not see any issues, do you know why I am seeing this problem? Can you help me ?

Thank you,

Bülent

[davidtosenovjan]

Crystal frequency does not affect ADC directly unless you don't have different system clock frequency. In the ADC control register there is configuration scaling down system clock frequency to ADC clocks that is needed to be 16MHz at most.

Please check system clock setting.