ESP32 Forum

Is it possible to use the SPI slave driver without defining a chip select?
I have a device that uses an interface very similar to SPI.
It has a MOSI, MISO and clock line, but no CS (chip select).

I would still like to use the SPI peripheral for this, instead of implementing some implementing it from scratch using interrupts from the clock line.

I tried initializing spics_io_num in spi_slave_interface_config_t as -1, but this results in an exception, when spicommon_cs_initialize is called from spi_slave_initialize: Is there a way to use the peripheral without the CS line via the ESP-IDF API?

Not really... while you may be able to wrangle the SPI hardware to work in a mode that is compatible with what you want, the driver is strictly transaction-based, with transactions being delineated by CS levels.

Hello,
Any idea on how to do "software" CS rather than using the CS pin state?
FYI: This is a capability supported by the STM32 microcontroler. See: https://electronics.stackexchange.com/q ... without-cs

Thx

You could use the pre_cb and post_cb callbacks to set/clear a GPIO that acts as CS.