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Board Suggestions Please for High DIO

Posted: Fri Apr 07, 2023 3:16 pm
by GadgetFreak
I have a project I want to make that needs around 96 directly controlled DIO pins. I had started the project with a Teensy4 but soon realised I could not use auto direction level shifters as these caused oscialltions in the signals. So I needed an extra 42 pins so I can control the IO direction individually on each level shifter.
So I need a board with high DIO count and a couple of SPI channels with a few select pins. It also needs to be capable of fast IO if possible and have a fairly high clock speed >280Mhz.
Does anyone have any suggestions for which STM32 board might work for me please?

Re: Board Suggestions Please for High DIO

Posted: Fri Apr 07, 2023 5:51 pm
by GadgetFreak
ok have been looking again at the confusing list of board variants.
Have looked closely at STM32F756ZG which on the overview page lists :
Up to 168 I/O ports with interrupt capability
Up to 164 fast I/Os up to 108 MHz
Up to 166 5 V-tolerant I/Os

I have also looked at NUCLEO-H723ZG & NUCLEO-U575ZI-Q but neither of these have the same IO listing on the overview.
So a question is are all 3 of these boards capable of this or is it just the STM32F756ZG that has 5v tolerant IO capability?

Re: Board Suggestions Please for High DIO

Posted: Fri Apr 07, 2023 6:20 pm
by ag123
for stm32 chips with lots of pins, there are things in the range of zg, zi, etc suffixes
e.g.
https://www.aliexpress.com/w/wholesale- ... 7zgt6.html
stm32f4 is fast (in terms of cpu speeds, mainly due to an on chip cache, but i'd guess it is an in-order processor)
then stm32h7 series is possibly among the fastest (*for cpu speeds*) for mcus, those are likely out-of-order execution , i.e. super pipelined processors.
in terms of io speeds both stm32f4xx and stm32h7xx has limits, this i'd think is less to do with the processor speeds than real electrical limits as to how fast io can go.
there are some of those boards as well
https://www.aliexpress.com/w/wholesale-stm32h7.html
then other than the online 'flea' markets, there is also Olimex that carry some boards
https://www.olimex.com/Products/ARM/ST/
and of course, ST itself has the Nucleo and Discovery boards, some of them has lots of pins
https://www.st.com/en/evaluation-tools/ ... oards.html
https://github.com/stm32duino/Arduino_Core_STM32