topic i.MX 8M Mini: SPI-bus native CS in i.MX Processors

i.MX 8M Mini: SPI-bus native CS

ristohedman — Tue, 17 Nov 2020 09:17:50 GMT

Hi,

I would like to ask NXP experts about SPI (ECSPI). My company is switching to iMX8 and in order to desighn the HW we need to know these details.

I've been studying

IMX8MMRM.pdf

8.1 External Signals and Pin Multiplexing

10.1 Enhanced Configurable SPI (ECSPI)

And asked my EVA- manufacturer but have not got an answer:

How are SPI chip selects SS1, SS2 and SS3 muxed to hardware pins, (or balls or pads - which way ever one calls them) ??

I heard that NXP is recommending to use gpio for chip selects (in Linux??) - is that true and if is, why?

Best Regards,

Risto H.

Re: i.MX 8M Mini: SPI-bus native CS

Yuri — Wed, 18 Nov 2020 06:29:55 GMT

@ristohedman
Hello,

Customers can use Table 8-1 (Muxing Options) of the i.MX8Mm RM.
As for pin assignments - use section 5 (Package information and contact assignments)
of i.MX8Mm Datasheet.

https://www.nxp.com/docs/en/data-sheet/IMX8MMCEC.pdf

GPIO instead of "native" SS may be used for non supported modes, say for "long"
messages.

Regards,
Yuri.

Re: i.MX 8M Mini: SPI-bus native CS

ristohedman — Wed, 18 Nov 2020 13:24:56 GMT

Hi,

Hmmm, now I must have a great misunderstanding, if I try to search e.g. ECSPI1_SS1 in any 'mini'- related document, I can not find ??!!

br, ristoH

Re: i.MX 8M Mini: SPI-bus native CS

Yuri — Thu, 19 Nov 2020 04:15:24 GMT

@ristohedman
Hello,

i.MX8Mm supports single eCSPI SS: ECSPI1_SS0 - there are no more (ECSPI1_SS1 ...).

https://community.nxp.com/t5/i-MX-Processors/How-can-I-use-ECSPI-SS1-2/m-p/848467

Regards,
Yuri.

Re: i.MX 8M Mini: SPI-bus native CS

ristohedman — Thu, 19 Nov 2020 07:17:44 GMT

Hi Yuri,

Finally an answer - not a good one for me but answer anyway.

BR, ristoH