Does nrf52833's spim support hardware csn pin selection?

[soloman]

Hi,

   I'm doing nrf52833's spi function.I want to use hardware slice selection instead of pulling the gpio pin, and the reference manual has the register IFTIMING.CSNDUR. However, the official SPIM initialization code shows that 52833 does not support spim extensions, which would cause the register IFTIMING.CSNDUR to not be configured.So, support or not?

Sincerely.

[Sigurd]

Hi!

The nRF52833 supports NRFX_SPIM_EXTENDED_ENABLED. The comment in the code is likely from the time before nRF52833 was released. 

[soloman]

Hi!

  Yes, I enabled the macro to try to send data using SPIM3 and do a data grab on the DuPont wire connected pins using the logic analyzer. And Two problems were found as follow:

   1. Some of the two SCKS have different crest widths, which should not occur in hardware-controlled SCKS.

   2. Modify the value of the register IFTIMING.CSNDUR and see no change.

Looking forward to your reply, thank you！

[Sigurd]

When you are calling

nrfx_spim_init(&spi, &spi_config, spim_event_handler, NULL) how did you configure the spi_config ?

[soloman]

nrfx_spim_init is in main after power_management_init().  config as follow picture:

[Sigurd]

So you have tried using different values of spi_config.ss_duration, correct?

[soloman]

yes! 

Another question is how to configure TXD.LIST? example,please.

[soloman]

hi！

   I assign spim end-event and task-start into an alloced ppi channel, and enabled end-start shortcut for controlling CSNDUR correctly between two transactions. It works forever, when tigger a task-start. So I fork the ppi with timer task-count.  And use a new ppi channel, which configuring timer compare[0] and ch_group[0].dis. The two ppi channels are included in ch_group[0]. It still always work, because the shortcut is opened. So how to stop spim transfer when spim end-start shortcut is enabled?

Looking forward to your reply, thank you！

[Sigurd]

Hi!

soloman said:

Another question is how to configure TXD.LIST? example,please.

I'm not aware of any examples.

soloman said:

So how to stop spim transfer when spim end-start shortcut is enabled?

You could try use the nrf_spim_shorts_disable() function to disable the short.