Re: Code Bounty

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katsmeow said...

It reads GPIO pins and then writes to some other GPIO pins, using OE(?), if i understand how you built it, so yes, it's very much what most of my projects need.

Yes, that's absolutely right, the demo SimonSays program demonstrates that.

said...

Perhaps you would know... there seems to be another point of misinformation (or maybe things have changed over the years) about reading and writing the pins, they can be read/written in 8bit groups, or all at once?

Hmm, not sure about that. Each pin can be set to read, write analogue or digital, and AFAIR, with EU and wiringPi you set these indicvidually. There may of course be a bottlenec with reading data that appears and disappears quickly of course.

said...

Is there handshaking of groups of pins, like "data is valid when status pin is low", or perhaps "send the next byte"?

Again, you have to set and read the pins individually with wiringPi.

said...

One discussion thread i ran across in urls Greg provided (which i am still reading thru) says IO speed can be severely limited by compilers generating branch predictions that fail, such as "while RDY pin is False do else read byte" (or however you like to write that), is OE running on the Pi subject to this or is it a C/Python/machine_code issue?

Sorry, don't know. Quick internet search though - The fastest continuous rate with an 8-bit ADC on a Pi Zero using SMI is 80 megasamples per second; the short-term burst rate can be higher.26 Aug 2020

Suggest you research yorself for your needs - what speed does the raspberry pi gpio work

said...

Kat

Do you have a raspberry Pi - if so the best suggestion I can make is set it up and experiment. Would be happy to handhold and guide you through a setup if you haven't done so already.

Cheers

Chris

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