M4 GPIO realistic maximal frequency ?

DBuer · ‎2019-08-18

How long does it take (approx) to rise or lower a GPIO pin fix configured to the M4 in the STM32MP157c, after issuing the command in the M4 code ? On our native STM32F409 board it takes around 10ns. I'm afraid the STM32MP1xx is much slower right ?

Regards,

Daniel

Olivier GALLIEN · ‎2019-08-20

Hi @DB.7uergin

Once a GPIO is allocated to M4 context there is no difference driving a GPIO from an MP1 M4 or STM32F4.

So no reason for a specific overhead here.

Did you measure something different to make this assumption ?

Br,

Olivier

Olivier GALLIEN
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DBuer · ‎2019-08-20

Hi Oliver

Ok thanks that sounds good. No i didn't measure anything on the MP1 Board, but i've made some bad experiences with other boards (i.MX7dual) where the GPIOs are quite slow (150 - 200ns) to raise or lower.

So it should be enough to lock my GPIO with "PERIPH_LOCK()" inside the M4 at the beginning of my code or do i need to update the DeviceTree ? I'm not sure if i already understood the ways of allocating the resources to either side (A7 or M4) :)

But anyway thanks for the answer.

Daniel