MCP23S08 SPI Expander driver for espidf

Original version: Alex Fabre

Driver Description

The driver is intended to work with any board which supports SPI. The user is required to provide implementation of the function int (*spi_transfer)(uint8_t *tx_buffer, uint8_t tx_len, uint8_t *rx_buffer, uint8_t *rx_len). Initialization sequence is descibed in the driver header file.

espidf example application

File main.c shows a minimal application to read and write data to the GPIO expander:

• SPI initialization
• spi_transfer function implementation
• MCP23S08 initialization
• FreeRTOS task which reads GPIO port and toggles its value

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