HOW CAN MAKE GPIO TOGGLE FASTER?

[JHY]

I use i.MX6DL with linux 3.0.35 and run GPIO toggle only.

From above tests, GPIO toggle is measured only 50KHz.

It is too slow, I think, so do I miss anything?

[lategoodbye]

Hi JHY,

please describe more in detail how you toggle the GPIOs (user space, kernel space).

Why do you need such high frequencies? For SPI or I2C?

Best regards

Stefan

[JHY]

How can I find references of assembler subrutines? Using that, is it possible to generate about 300KHz in linux?

[lategoodbye]

By the way there is also another way from userspace: http://chiragnagpal.com/examples.html

[igorpadykov · Accepted solution]

one can find assembler examples in folder

uboot/cpu/arm_cortexa8

it is not possible to answer if it will generate about 300KHz in linux,

since this depends on board configuration. Only running test on real board

can answer on that.

[igorpadykov]

Hi JHY

in general Linux is not real time system, it can have

large delays. In particular one can look at context switching

delays:

LMbench Benchmarks on i.MX

Probably you can write assembler subrouite for GPIOs or use

realtime OS like QNX.

Best regards

igor

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