S32K148 SPI Pal slave

cancel
Showing results for 
Search instead for 
Did you mean: 

S32K148 SPI Pal slave

482 Views
antoine_monmarc
Contributor V

Hello,

I'm using SPI slave on a S32K148EVB board.

My code is based on the spi_pal demo.

For master part I'm using either:

- (1) S32K148EVB with spi_pal demo

- (2) S32K148EVB with lpspi_dma demo

- (3) Raspberry PI

here is my slave configuration:

pastedImage_5.png

The slave behavior is correct with the master (1) and (2) but when using master (3) the MISO pin is not in the good state when the clock starts, resulting in bit shifts.

Bad case:

In the case of master (3) the SS pin is enabled (low) 11.8µs before the clock starts:

pastedImage_1.png

And the MISO pin doesn't go LOW after SS pin is enabled. 

At first clock falling edge, the MISO pin is not correct.

Good case:

In case of master (1) and (2) the MISO pin behavior is like this:

pastedImage_2.png

At first clock falling edge, the MISO pin is correct.

is there any reason why the MISO pin will not go LOW when SS pin is enabled?

the baudrate I'm using is different, for master (3) I'm using 5M and for (1) and (2) I tried 1M maximum, but I don't believe it should make a difference for MISO pin.

1 Reply

333 Views
antoine_monmarc
Contributor V

Hello,

We found the solution by changing the slave configuration of "Phase" to "Read on second edge".

We also changed the configuration of master (3) to adapt to this configuration.