AM3358: McSPI channels

Hi,

What software are you using?

QNC RTOS

Thanks. We cannot help with QNC, but I have asked the McSPI experts to comment from hardware point of view. They will respond here.

Hi. Still haven't heard back yet. Thanks.

Hi Daniel,

In general, it is possible to use a GPIO as a SPI CS. This e2e thread has some additional details: e2e.ti.com/.../425326

I'm still looking into your FIFO question.  However, in case you haven't already seen in the TRM, please note that "when more than one channel has an FIFO enable bit field (FFER or FFEW) set, the FIFO will not be used on any channel. Software must ensure that only one enabled channel is configured to use the FIFO buffer" (section 24.3.2.1 in the AM335x TRM).

Regards,
Melissa

Hi Melissa,

Yes, I know about only 1 FIFO being enabled at a time. I guess my questions are more along the lines of the following.
Can ANY one channel be used for multiple devices, even using the FIFO of the given channel. In other words, as long as
you see the config and ctrl properly for a given SPI slave device before starting a transaction on the channel, there does
not seem to me to be anything preventing one from using only channel of the controller for many SPI devices. The fact
that there are 4 devices seems to be mostly a convenience of set up, such that the clock rate, word length, phasing and
other SPI device specific settings do have to be redone each time. But if you are willing to redo these before each slave
device access then you can use a single channel only. OR, you can do also as I was alluding to, using 3 channel for each
of 3 different slave devices and use the 4th channel for 2 or more additional slave devices. Is this correct?

A final question. Is DMA available on all 4 channels?

Thanks.
Dan

Hi Melissa,

Still waiting on your response. Thanks.

Hi Melissa,

Can you please provide a response to my last questions?