Hello,
the SPI does work with NSSP(Negative Slave Select Pulse-Mode), but it does not work if I disable NSSP. As someone pointed out the SPI NSS(P) may only work if the Pulldown of that pin is enabled, but I’m not 100% sure on that one, but it seems to wirk for NSSP-En that way. For NSSP-Disabled I could not get the SPI-Controller to control the NSS(CS).
I observed two issues:
1) On Reset the NSS(CS) is low and will stay low until the first SPI Transaction. I tried to set it via HAL_GPIO_WritePin( … , GPIO_PIN_SET); but that has no effect, maybe because the Pin is controlles by the SPI-HW.
2) Is the serious issue is, if I disable the NSSP, the CS does not work at all.
How can I make the Hardware NSS work with NSSP disabled?
Thanks a lot, Best Regards, Seppel
P.S.
This is the Setup and Waverforms for the NSSP-Disabled, I have a 2s delay on startup, which you can see on the scope-pictures.:
This is the setup for the NSSP Enabled, the same was used for NSSP-Disabled(only that NSSP was set to disable. ,I have a 2s delay on startup, which you can see on the scope-pictures.:
