increase number of pins in flexcom interface

This forum is for users of Microchip MPUs and who are interested in using Linux OS.

Moderator: nferre

yawimiki
Posts: 8
Joined: Thu Jun 04, 2020 9:26 am

increase number of pins in flexcom interface

Mon Jul 20, 2020 5:06 am

Hi everyone,
I am using SPI in sama5d27 development board. I am using flexcom4 which only use 5 pins. So therefore, only two chip select can be used when we use SPI. Are there any method to increase the number of pins allocated in the flexcom4 to increase the number of CS pins for SPI?
cheers
nferre
Site Admin
Posts: 221
Joined: Wed Feb 14, 2007 11:17 am

Re: increase number of pins in flexcom interface

Mon Jul 20, 2020 2:05 pm

Hi,

There is a feature to configure up to 4 CS for a SPI controller controlled by Fixed the value in SPI_MR.Peripheral Select. There is additional possibility to have more CS by using the Chip Select Decode feature. In Linux you can also use regular GPIO as CS for SPI.

Note that it's even easier with newer kernels (5.5 onwards). Check this explanation and fixes:
https://lore.kernel.org/linux-arm-kerne ... otlin.com/

Regards
yawimiki
Posts: 8
Joined: Thu Jun 04, 2020 9:26 am

Re: increase number of pins in flexcom interface

Tue Jul 21, 2020 3:45 am

Hi nferre,
Thank you very much for your recommendation to use GPIO as CS. At the moment I use GPIOs, I will consider that kernal solution for my next version of the product.
Thanks, regards,
YW
yawimiki
Posts: 8
Joined: Thu Jun 04, 2020 9:26 am

Re: increase number of pins in flexcom interface

Tue Aug 04, 2020 3:02 am

Hi nferre,
Could you please tell me how to change the value in SPI_MR.Peripheral Select ? because it seems GPIOs take so much time in my application.

cheers!!!

Return to “LINUX”

Who is online

Users browsing this forum: Baidu [Spider] and 6 guests