Three external ADC's connected to STM32F7

[Koen Ie]

Posted on March 16, 2018 at 22:06

Currently I am doing a project to develop a system with three external ADC's. I want to read the 3 ADC's at the same time.

I bought the following components

• 3x ADS1256 /

  http://www.ti.com/lit/ds/symlink/ads1256.pdf

• 1x STM32F7 /

  http://www.st.com/en/evaluation-tools/nucleo-f767zi.html

I want to configure the STM32 as 3 Master SPI controllers and connect every ADS1256 (with the highest sample rate) to the STM32 board.

All the data needs to be transfered over UART to a PC to do further data processing.

I was wondering if that would be possible and if someone has tips how to accomplish this.

I didn't see a library for the HAL interface between ADS1256 and STM32, I want to port an existing library to HAL.

Kind regards

Koen

[Michal Dudka]

Posted on March 18, 2018 at 09:50

ADC1256 has sample rates to 30ksps, i think there is no need to read data from them simultaneously. I think that you can trigger all three conversion by 'SYNC' input in one time and then read data separately. If it's not possible (for example due HW connections) you can try to set three SPI's in slave mode and connect Serial output from each ADC to one of theese SPI's. One (4th) SPI configure in master mode and connect to ADC Serial Data In and to ADC and SPI slaves clock. Then you can theoreticaly receive three datastreams at one time.