SPI Chip Select Behavior

[moose]

Shouldn't chip select signal stay asserted for the entire transmission of a multi-byte frame? When I send an 8-byte frame, I see the CS go high after every byte, as shown below. Is this expected? Is there a way to configure it to stay asserted throughout the frame? I tried both spidev_test and spi-pip and experienced the same behavior. Below are the user space commands I tried. Any input? Thx!

`spidev_test -D /dev/spidev1.0 -v -p "\x55\x55\x55\x55\x00\x00\xff\xff"`

`printf '\x55\x55\x55\x55\x00\x00\xff\xff' | spi-pipe -d /dev/spidev1.0 --blocksize=8 | hexdump -C`

CH1 (yellow) = SPI_CLK

CH2 (blue) = SPI_nCS

[brian14]

Hi @moose, 

Thank you for contacting NXP Support.

No, that is not the expected behavior. I have tested on my side using the BSP version 6.1.55 and here are my results.

Could you please tell me your BSP, your processor and if you are using an EVK or custom board?