Configure mbed-os-example-lorawan for the SX1272/62

howto.md

These instructions are for customizing the following project: https://os.mbed.com/teams/mbed-os-examples/code/mbed-os-example-lorawan/

Once you've imported it, then grab the sample mbed_app.json config file for your radio in the config/ folder and move it to mbed_app.json in the project root.

Edit it as follows:

Update the target_overrides catch-all ("*") section with your device info from TTN:

"target_overrides": {
        "*": {
            "platform.stdio-convert-newlines": true,
            "platform.stdio-baud-rate": 115200,
            "platform.default-serial-baud-rate": 115200,
            "lora.over-the-air-activation": true,
            "lora.duty-cycle-on": true,
            "mbed-trace.enable": true,
            "lora.phy": "US915",
            "lora.fsb-mask": "{ 0xFF00, 0x0000, 0x0000, 0x0000, 0x0002 }",
            "lora.device-eui": "{ 0x00, 0x35, 0x07, 0x25, 0x67, 0x09, 0x16, 0x45 }",
            "lora.application-eui": "{ 0x70, 0xB3, 0xD5, 0x70, 0xD0, 0x02, 0xE4, 0x23 }",
            "lora.application-key": "{ 0x1F, 0x46, 0xBD, 0x2F, 0x86, 0x6D, 0xD6, 0x88, 0xC3, 0x99, 0x6D, 0x1A, 0xAF, 0x86, 0x6E, 0x9E }",
            "lora.appskey": "{ 0xCA, 0x9B, 0x50, 0xB1, 0x5C, 0x8E, 0xF9, 0x7B, 0x62, 0x32, 0xB2, 0x6A, 0xB0, 0x09, 0xAD, 0x0A }",
            "lora.nwkskey": "{ 0xB9, 0x76, 0x1E, 0x36, 0x3A, 0x5A, 0xA9, 0xE5, 0xB3, 0x33, 0xBE, 0x03, 0x76, 0x8B, 0xCA, 0x8F }", 
            "lora.device-address": "0x2632488"
        },

In particular, note the following lines for configuring the radio for Canada:

            "lora.phy": "US915",
            "lora.fsb-mask": "{ 0xFF00, 0x0000, 0x0000, 0x0000, 0x0002 }",

The lora.nwkskey, lora.appskey and lora.device-address are only need if you want ABP mode. If you do, you also need to set lora.over-the-air-activation: false.

Then, depending on your device, add a section directly below the catch-all ("*") for the NRF52_DK for your LoRa radio.

If you're using the SX1262 use the following pins:

        "NRF52_DK": {
            "lora-spi-mosi":       "D11",
            "lora-spi-miso":       "D12",
            "lora-spi-sclk":       "D13",
            "lora-cs":             "D7",
            "lora-reset":          "A0",
            "lora-dio1":           "D5",
            "lora-busy":           "D3",
            "lora-freq-sel":       "A1",
            "lora-dev-sel":        "A2",
            "lora-xtal-sel":       "A3",
            "lora-ant-switch":     "D8"
        },

And if you're using the SX1272 then:

        "NRF52_DK": {
            "lora-spi-mosi":       "D11",
            "lora-spi-miso":       "D12",
            "lora-spi-sclk":       "D13",
            "lora-cs":             "D10",
            "lora-reset":          "A0",
            "lora-dio0":           "D2",
            "lora-dio1":           "D3",
            "lora-dio2":           "D4",
            "lora-dio3":           "D5",
            "lora-dio4":           "A3",
            "lora-dio5":           "D9",
            "lora-rf-switch-ctl1": "NC",
            "lora-rf-switch-ctl2": "NC",
            "lora-txctl":          "NC",
            "lora-rxctl":          "NC",
            "lora-ant-switch":     "A4",
            "lora-pwr-amp-ctl":    "NC",
            "lora-tcxo":           "NC"
        },

Note: I'm not entirely convinced I've got this pin configuration entirely correct. Packets are sent and received by TTN but they arrive irregularly (more than the SX1262) and often only 1 or 2 rather than continuous. I just read https://os.mbed.com/components/SX1276MB1xAS/ and made it up from there.