High-speed GPIOs - Printable Version

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High-speed GPIOs - dsnyder - 05-05-2016

Is there support to directly control the GPIO pins with C or assembly, directly?

I'm looking to control the GPIOs at 10Mhz to 100Mhz and i assume that is not possible using the Python GPIO interface.

RE: High-speed GPIOs - martinayotte - 05-05-2016

If you look at that thread, you will see that python pyA20 library is now working with an easy fix.
There are some others too, such RPi.GPIO. But since you wish to use plain C, you can still look at the code of pyA20, the GPIO accesses are done via memory-map.
But I doubt in any cases that you will be statisfied with the speed, because the range of 10Mhz to 100Mhz is almost impossible, at least in user-space, since the kernel still needs seom CPU cycles.
What do you wish to achieve ? Maybe an hardware solution can fit better your needs...

RE: High-speed GPIOs - dsnyder - 05-05-2016

i'm looking to control and monitor the pins of a 2Mhz microprocessor in real-time with a minimum of external hardware. i will need to control the GPIOs with less than 100ns access time.

the A64 user manual indicates that this should be possible.

RE: High-speed GPIOs - martinayotte - 05-05-2016

Understood !
But what requires such high speed ? Monitoring, yes, but at which level ? looking at the second MCU address/data bus directly ?
Is that required for some "In circuit Real Time Debugging" ?
Otherwise, I don't see the requirements ... Handshaking between MCUs doesn't require any high speed ...