3-wire Interface on nRF52?

RE: 3-wire Interface on nRF52?

wdu — Mon, 24 Jul 2017 09:10:34 GMT

Set MISO or MOSI to disconnected (0xffffffff) while doing write resp read. Reconfigure the SPI block as needed while keeping CS asserted when the IO direction has to change. Since most SPI devices I know will require no or one direction change per command, you'd have to split the transaction in at most two parts. I do this with the SPI block, haven't worked with SPIM yet.

RE: 3-wire Interface on nRF52?

jcondon — Thu, 20 Jul 2017 21:45:25 GMT

wdu, where are you seeing 3-wire SPI support (w/ combined MISO/MOSI?). On the product specification I see 3 distinct pins for CLK, MISO, and MISO not the two pins required (CLK & MISO/MOSI). There is also nowhere I can find in the SPIM block that mentions it.

RE: 3-wire Interface on nRF52?

wdu — Mon, 19 Dec 2016 14:13:45 GMT

This information is not correct. At least the SPI block supports 3-wire SPI (combined MISO/MOSI), and I suspect the SPIM block also supports it.

RE: 3-wire Interface on nRF52?

jcondon — Fri, 16 Oct 2015 15:28:24 GMT

That's too bad. It would be nice to get those IO back.

RE: 3-wire Interface on nRF52?

Anders Strand — Fri, 16 Oct 2015 09:30:17 GMT

Hi.

The nRF52 will not have built in support for combining the MISO and MOSI line. If you are using a 3-wire device, you can connect MOSI to MISO with a 10k resistor like this guide does.

-Anders