remapping SPI with IO34 and IO35 like MOSI and CLK

nicola
Posts: 22
Joined: Mon Feb 18, 2019 8:04 am

remapping SPI with IO34 and IO35 like MOSI and CLK

Postby nicola » Thu Jun 18, 2020 11:28 am

Hi to everyone,
I want to map the SPI interface to the following configuration (I know that IO34 and IO35 can be used just as input)

MOSI: IO34
CLK:IO35
CS:IO33
MISO:IO25

Is this possible ?

Awaiting your kind reply
Thanks in advance.
Nicola

nicola
Posts: 22
Joined: Mon Feb 18, 2019 8:04 am

Re: remapping SPI with IO34 and IO35 like MOSI and CLK

Postby nicola » Thu Jun 18, 2020 5:02 pm

Hi,
sorry, could you please clear my doubts about this configuration?

Awaiting your kind reply.
Thanks.
Nicola

PeterR
Posts: 621
Joined: Mon Jun 04, 2018 2:47 pm

Re: remapping SPI with IO34 and IO35 like MOSI and CLK

Postby PeterR » Thu Jun 18, 2020 6:47 pm

If you're pins support the direction (you are not trying to make an input pin act as MOSI) then sure, yes.
You should consider that if you do swap to non default pins then the GPIO mux will kick you and limit you're maximum achievable SPI clock. The calculations are posted within ESP's SPI documentation and depend in part on which SPI device you use.
My experience has been that (generally) you will be limited to around 8MHz when using non standard SPI pins. Theoretical suggest 12 MHz. I would accept that the difference may be down to my lay out man having had a 'lads' night out before posting his Gerbers.
Just to say check the Wiki and then derate a bit.
& I also believe that IDF CAN should be fixed.

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