rp2xxx Directory Reference

Detailed Description

Gecko Backend for rp2xxx

Usage

// Store the bus instance somewhere
struct joybus_rp2xxx rp2xxx_bus;
 
// Initialize the rp2xxx joybus interface
// Parameters: (joybus_rp2xxx instance, GPIO, PIO instance)
joybus_rp2xxx_init(&rp2xxx_bus, 6, pio0);
 
// Cast to a generic joybus pointer, for ease of use with libjoybus functions
struct joybus *bus = JOYBUS(&rp2xxx_bus);
 
// Enable the bus
joybus_enable(bus);
 
// Use the bus
joybus_transfer(bus, ...);

Checklist

• Backend must implement all functions in joybus_api

• Transfers must fail with JOYBUS_ERR_DISABLED if backend is not enabled

• Transfers must fail with JOYBUS_ERR_BUSY if another transfer is in progress

• Transfers must fail with JOYBUS_ERR_TIMEOUT if target does not begin replying within 100 µs

• Transfers must fail with JOYBUS_ERR_TIMEOUT if each subsequent byte is not received within 100 µs

• Backend must enforce a minimum delay of 20 µs between each transfer

• Target must begin responding to any command within 100 µs

• When target read mode is enabled, the bus must be idle before reading data to ensure we are not in the middle of a transfer

• If an error occurs during a target read, wait for the bus to be idle before starting to read the next command

Ideally, your backend should also meet the following criteria:

• Target must begin responding to any command within 10 µs

• Backend supports 4 simultaneous buses
• Zephyr implementation available