Python LT8900 via SPI

This Python module enables a Python to talk to an LT8900 radio attached to an serial peripheral interface (SPI).

API

Synopsis

lt8900_spi.radio(spi_bus, spi_dev, config = None) -> instance
lt8900_spi.radio.put_register(reg, value) -> value
lt8900_spi.radio.put_register_bits(reg, bits_dict) -> value
lt8900_spi.radio.get_register(reg) -> value
lt8900_spi.radio.get_register_bits(reg, value = None) -> dictionary
lt8900_spi.radio.configure(config) -> None
lt8900_spi.radio.initialize() -> boolean
lt8900_spi.radio.set_channel(channel) -> dictionary
lt8900_spi.radio.set_syncword(syncword) -> None
lt8900_spi.radio.fill_fifo(message, include_length = True) -> list
lt8900_spi.radio.transmit(message, channel = None) -> boolean
lt8900_spi.radio.multi_transmit(message, channels, retries = 3, delay = 0.1) -> boolean
lt8900_spi.radio.start_listening(channel) -> boolean
lt8900_spi.radio.stop_listening() -> boolean
lt8900_spi.radio.receive(channel = None, wait = False, length = None, wait_time = 0.1) -> list

instance.get_register_bits

Low-level primitive to get a named register with bitfields expanded to names.

instance.put_register_bits

Low-level primitive to set a named register by bitfield value.

instance.set_syncword

High-level interface to syncword mechanism. The syncword can be 1, 2, 3, or 4 16-bit words long and should be provided as an array.

Example:

instance.set_syncword([1, 2, 3, 4])

instance.transmit

Transmit a message. If a channel is specified transmit on that channel -- otherwise the current channel is queried and then used.

instance.multi_transmit

Transmit a message across multiple channels multiple times. This is a common pattern so this function is provided for convience.

Example

#! /usr/bin/env python3

import time

import gpiozero
import lt8900_spi

# Need to keep this attached to drive the line high -- if the object disappears then
# the GPIO port gets reconfigured as an input port
# Note broadcom pin numbers are used
reset_gpio = gpiozero.LED(24)
reset_gpio.on()
def reset_module_via_gpio():    
	reset_gpio.off()
	time.sleep(0.1)
	reset_gpio.on()
	time.sleep(0.1)

radio = lt8900_spi.radio(0, 0, {
	'reset_command': reset_module_via_gpio
})

if not radio.initialize():
	raise ValueError('Initialize failed')

radio.set_syncword([0x258B, 0x147A])

radio.multi_transmit([0xB0, 0x51, 0xF0, 0x00, 0x00, 0x01, 212], [9, 40, 71], delay = 0.5)