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DBuer
Associate II
August 18, 2019
Question

M4 GPIO realistic maximal frequency ?

  • August 18, 2019
  • 2 replies
  • 834 views

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

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2 replies

Olivier GALLIEN
ST Technical Moderator
August 20, 2019

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

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DBuer
DBuerAuthor
Associate II
August 20, 2019

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