SPI: writing data for transmission, what flags to check?
Hi,
it seems I have some general problem with the understanding of the SPI transmission with the STM32H5.
I have an SPI, configured as master for transmission only. Initialisation and stuff is done by CubeMX-generated code, but the transmission shall be done more or less "manually". Means: I want to send 3x 1 byte by writing them one after an other into the related TXDR register.
Now what I do NOT understand is, what flag do I have to wait for in order to see if a) I can write the next byte into the FIFO and b) see if all three bytes have been sent?
From my understanding:
a) can be achieved by waiting for the TXP-flag being set. As long as this is the case, I can write the next byte.
b) can be achieved by waiting for the TXC-flag being set. As soon as this is the case, all data have been transmitted.
However, there seems to be a dependency to the CR2-register. When I set it to 0,TXP appears once and then never again. When I set it to 3, TXC never appears.
So I can't find a situation where I can write data to the transmission register properly AND where I'm informed about the transmission being complete.
This all is done without any interrupts and without the blocking transmission-functions out of the HAL.
Can anybody sched some light on the behaviour of these flags?
Thanks!