[Answered] SPI: Use of the queue_size property in spi_device_interface_config_t
Posted: Tue Jan 10, 2017 7:57 pm
When using the SPI master driver, I need to call spi_bus_add_device()
http://esp-idf.readthedocs.io/en/latest ... e_handle_t
Which takes as input a struct spi_device_interface_config_t
http://esp-idf.readthedocs.io/en/latest ... e_config_t
which has a property called queue_size
http://esp-idf.readthedocs.io/en/latest ... ueue_sizeE
My question is ... what is a "good" value for queue_size? How does one size correctly? What are the "units of queue_size"? (transactions, data bytes, individual requests etc etc?).
I had assumed that if I was going to use spi_device_transmit() that I wouldn't need a queue so tried to specify 0 but that asserted immediately.
http://esp-idf.readthedocs.io/en/latest ... e_handle_t
Which takes as input a struct spi_device_interface_config_t
http://esp-idf.readthedocs.io/en/latest ... e_config_t
which has a property called queue_size
http://esp-idf.readthedocs.io/en/latest ... ueue_sizeE
My question is ... what is a "good" value for queue_size? How does one size correctly? What are the "units of queue_size"? (transactions, data bytes, individual requests etc etc?).
I had assumed that if I was going to use spi_device_transmit() that I wouldn't need a queue so tried to specify 0 but that asserted immediately.