It it possbile to enable 2 way output for 1 SPI beside just MOSI?

StephanMair · ‎2013-03-03

Posted on March 04, 2013 at 03:51

It is possible to have two serial outputs under master mode for one SPI? I need to drive two groups of devices at the same time with DIFFERENT data on ONE clock signal.

That is, I need and only need one clock signal, but two outputs that give out different, independent data.

Is it possible?

Tesla DeLorean · ‎2013-03-03

Posted on March 04, 2013 at 04:16

Look at I2S/EXT and SDIO

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StephanMair · ‎2013-03-03

Posted on March 04, 2013 at 06:26

Thank you for your help.

Could you be a little bit more specific, please? I meant to drive some 74595s, simple stuff, so no need to format my data with any kind of header, which is, as far as I know, something SDIO tends to do.

raptorhal2 · ‎2013-03-04

Posted on March 04, 2013 at 16:43

It is not very elegant, but you can bit bang GPIOs to make your own custom SDI. Use one pin as enable, two pins as data out, two pins as data in, and one pin as clock.

Document it well.

Cheers, Hal

Tesla DeLorean · ‎2013-03-04

Posted on March 04, 2013 at 17:57

If the bit counts are relatively small, and speed/timing is not critical, GPIO bit banging might make the most sense.

I believe I2S can bond two channels together, but I don't plan on demonstrating a solution. SDIO offers some possibilities with 1/4/8-bit clocked data

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waclawek.jan · ‎2013-03-04

Posted on March 04, 2013 at 19:07

One SPI as master and one more as slave might probably do the job, too.

I could also envisage the respective I2Sext being driven from the module set to ''regular SPI'' mode, too; although I am not going to prove this either.

JW