2008-09-17 20:19:56 Any way to synchronize GPIO outputs on BF54x?
Isaac Leung (CANADA)
Is it possible to synchronize outputs on the GPIO pins on BF547/BF548? (Or close enough to being synchronous...)
I've got several GPIO pins that control an external device. The logic more or less works so I know everything is pretty much functioning. It's "less working" because the time it takes for me to control all the pins one at a time is too slow so not everything works all the time.
e.g. I have something like:
write(Signal1, "0", 1);
write(Signal2, "1", 1);
The problem is that the lag between the 2 signals is something like 10us. I need it to be more like 5us, so anything faster than that is good enough to be considered "synchronous" here. Doesn't sound very demanding. I don't need the signals to _toggle_ quickly, it can be quite slow, but they do need to line up. Can I line up the operations and then trigger them all at once?
Is this possible? I just don't want to resort to doing a special GPIO driver if there's a better way.
2008-09-17 20:27:38 Re: Any way to synchronize GPIO outputs on BF54x?
Mike Frysinger (UNITED STATES)
using the GPIO simple driver, no ... nor is it architected for such things
you would need to write a special driver, or extend the simple gpio driver
i imagine you could do it easily using the simple gpio driver and like an ioctl interface ... give it a small array of values to cram into the respective port direction mmr's