Basic examples of MicroPython LoRa modem driver use

context.md

See:

• micropython/micropython-lib#501
• micropython/micropython#9130

rxtx_async.py

import time
import uasyncio
import async_modem


# these match the default's in Heltec's library, apart from freq_khz
lora_cfg = {
    "sf": 11,
    "bw": 125,
    "freq_khz": 917000,
    "coding_rate": 5,
    "preamble_len": 8,
    "invert_iq_tx": False,
    "syncword": 0x12,
}


def modem_sx1276():
    from machine import SPI, Pin
    import sx1276

    spi = SPI(
        0,
        baudrate=2000_000,
        polarity=0,
        phase=0,
        sck=Pin(6),
        mosi=Pin(7),
        miso=Pin(4),
    )
    cs = Pin(9, mode=Pin.OUT, value=1)

    # TODO:" this seems to be a bug in the SX1276 compared to SX1262
    lora_cfg["invert_iq_tx"] = not lora_cfg["invert_iq_tx"]

    return sx1276.SX1276(spi, cs,
                         dio0=Pin(10, mode=Pin.IN),
                         dio1=Pin(11, mode=Pin.IN),
                         radio_reset=Pin(13, mode=Pin.OPEN_DRAIN),
                         lora_cfg=lora_cfg)


def modem_sx1262():
    from machine import SPI, Pin
    import sx1262

    # Parameters match the Waveshare Pico-LoRa-SX1262 module
    spi = SPI(
        1,
        baudrate=2000_000,
        polarity=0,
        phase=0,
        sck=Pin(10),
        mosi=Pin(11),
        miso=Pin(12),
    )
    cs = Pin(3, mode=Pin.OUT, value=1)

    return sx1262.SX1262(spi, cs,
                         busy=Pin(2, mode=Pin.IN),
                         dio1=Pin(20, mode=Pin.IN),
                         radio_reset=Pin(15, mode=Pin.OUT),
                         dio2_rf_sw=True,
                         dio3_tcxo_millivolts=3300,
                         lora_cfg=lora_cfg)


def modem_stm32wl5():
    import stm32wl5
    return stm32wl5.WL55SubGhzModem(lora_cfg)



# m = modem_stm32wl5()
m = modem_sx1276()
# m = modem_sx1262()

m = async_modem.AsyncModem(m)


async def rxtx_forever_coro(m):
    print("Running with async...")
    while True:
        print("Receiving...")
        ts = time.ticks_ms()
        message = await m.receive(2000)
        if message:
            print("Message: {!r}".format(message))
        else:
            print("Timeout after {}ms".format(time.ticks_ms() - ts))
        print("Transmitting...")
        await m.transmit(b"Hello, I'm async MicroPython")


uasyncio.run(rxtx_forever_coro(m))

rxtx_sync.py

import time

# these match the default's in Heltec's library, apart from freq_khz
lora_cfg = {
    "sf": 11,
    "bw": 125,
    "freq_khz": 917000,
    "coding_rate": 5,
    "preamble_len": 8,
    "invert_iq_tx": False,
    "syncword": 0x12,
}


def modem_sx1276():
    from machine import SPI, Pin
    import sx1276

    spi = SPI(
        0,
        baudrate=500_000,
        polarity=0,
        phase=0,
        sck=Pin(6),
        mosi=Pin(7),
        miso=Pin(4),
    )
    cs = Pin(9, mode=Pin.OUT, value=1)

    # TODO:" this seems to be a bug in the SX1276 compared to SX1262
    lora_cfg["invert_iq_tx"] = not lora_cfg["invert_iq_tx"]

    return sx1276.SX1276(spi, cs,
                         dio0=Pin(10, mode=Pin.IN),
                         dio1=Pin(11, mode=Pin.IN),
                         radio_reset=Pin(13, mode=Pin.OPEN_DRAIN),
                         lora_cfg=lora_cfg)


def modem_sx1262():
    from machine import SPI, Pin
    import sx1262

    # Parameters match the Waveshare Pico-LoRa-SX1262 module
    spi = SPI(
        1,
        baudrate=2000_000,
        polarity=0,
        phase=0,
        sck=Pin(10),
        mosi=Pin(11),
        miso=Pin(12),
    )
    cs = Pin(3, mode=Pin.OUT, value=1)

    return sx1262.SX1262(spi, cs,
                         busy=Pin(2, mode=Pin.IN),
                         dio1=Pin(20, mode=Pin.IN),
                         radio_reset=Pin(15, mode=Pin.OUT),
                         dio2_rf_sw=True,
                         dio3_tcxo_millivolts=3300,
                         lora_cfg=lora_cfg)


def modem_stm32wl5():
    import stm32wl5
    return stm32wl5.WL55SubGhzModem(lora_cfg)



# m = modem_stm32wl5()
# m = modem_sx1276()
m = modem_sx1262()


def rxtx_sync(m):
    while True:
        ts = time.ticks_ms()
        print("Receiving...")
        message = m.receive(2000)
        if message:
            print("Message: {!r}".format(message))
        else:
            print("Timeout after {}ms".format(time.ticks_ms() - ts))
        print("Transmitting...")
        m.transmit(b"Hello, I'm sync MicroPython")


rxtx_sync(m)