Can I use the Slave Selects more than 4 existing ones in SPI of Flexcomm?

[toipaz]

We designed the circuit and connected eight SPI slaves to one SPI bus.
(Of course, each CS is connected by each GPIO respectively.)

I just checked, and Flexcomm supports up to four Slave select...
When I looked at the SDK code, there was no way to control CS using GPIO.

When using SPI of Flexcomm, can I use a separate GPIO to use Slave Select more than four existing ones?

[Alexis_A · Accepted solution]

Hello @toipaz,

This should be possible, only you would need to be careful about the timing for the SSEL.

Best Regards,

Alexis Andalon

[toipaz]

thanks for your reply.

Yes. I'm trying it.

I'm asking the next question because there seems to be a timing issue.

https://community.nxp.com/t5/LPC-Microcontrollers/Using-SPI-of-Flexcomm-with-GPIO-CS-in-LPC54608-the...

[toipaz]

1. Set the pin mux to GPIO without SSEL0~SSEL3 func.
2. SPI driver code controls each CS using GPIO before and after communication.
Is it possible to use this method?