Add BLE primitives

[MaartenS11]

Mostly glue code that exposes parts of the zephyr bluetooth API to wasm using primitives. I was able to do most of that using claude with some manual intervention. I have currently only tested this on the ESP32 C3 super mini.

Below is an example of a robot that is controlled using BLE, the user can send the messages, forward, left, right to make the robot move. I have tried this by sending commands from my mac and also from my phone using the nRFConnect app.

@external("env", "chip_digital_write") declare function chip_digital_write(pin: i32, value: i32): void;
@external("env", "chip_pin_mode") declare function chip_pin_mode(pin: i32, mode: i32): void;
@external("env", "chip_delay") declare function chip_delay(time: i32): void;

@external("env", "ble_enable") declare function ble_enable(nameAddr: ArrayBuffer, nameLen: i32): i32;
@external("env", "ble_service_create") declare function ble_service_create(uuidAddr: ArrayBuffer, uuidLen: i32): i32;
@external("env", "ble_characteristic_create") declare function ble_characteristic_create(service: i32, uuidAddr: ArrayBuffer, uuidLen: i32, properties: i32, permissions: i32): i32;
@external("env", "ble_characteristic_read") declare function ble_characteristic_read(index: i32, bufAddr: ArrayBuffer, len: i32): i32;
@external("env", "ble_characteristic_available") declare function ble_characteristic_available(index: i32): i32;
@external("env", "ble_advertise_start") declare function ble_advertise_start(): i32;
@external("env", "ble_connected") declare function ble_connected(): bool;

enum PinMode {
    Input = 0,
    Output = 2
}

// Bit values from Zephyr's bt_gatt_chrc/bt_gatt_perm enums.
const CHRC_WRITE: i32 = 0x08;
const CHRC_WRITE_NO_RESP: i32 = 0x04;
const PERM_WRITE: i32 = 0x02;

function uuid(b0: i32, b1: i32, b2: i32, b3: i32, b4: i32, b5: i32, b6: i32, b7: i32,
             b8: i32, b9: i32, b10: i32, b11: i32, b12: i32, b13: i32, b14: i32, b15: i32): ArrayBuffer {
    const buf = new Uint8Array(16);
    buf[0] = b0; buf[1] = b1; buf[2] = b2; buf[3] = b3;
    buf[4] = b4; buf[5] = b5; buf[6] = b6; buf[7] = b7;
    buf[8] = b8; buf[9] = b9; buf[10] = b10; buf[11] = b11;
    buf[12] = b12; buf[13] = b13; buf[14] = b14; buf[15] = b15;
    return buf.buffer;
}

// Nordic UART Service UUIDs, recognised by most generic BLE terminal apps
// (e.g. "Serial Bluetooth Terminal", nRF Connect) so no custom phone app is
// needed to send commands.
function serviceUuid(): ArrayBuffer {
    return uuid(0x6e, 0x40, 0x00, 0x01, 0xb5, 0xa3, 0xf3, 0x93, 0xe0, 0xa9, 0xe5, 0x0e, 0x24, 0xdc, 0xca, 0x9e);
}

function commandUuid(): ArrayBuffer {
    return uuid(0x6e, 0x40, 0x00, 0x02, 0xb5, 0xa3, 0xf3, 0x93, 0xe0, 0xa9, 0xe5, 0x0e, 0x24, 0xdc, 0xca, 0x9e);
}

function stop(): void {
    chip_digital_write(0, 1);
    chip_digital_write(1, 1);
    chip_digital_write(2, 1);
    chip_digital_write(3, 1);
}

function forward(): void {
    chip_digital_write(0, 1);
    chip_digital_write(1, 0);
    chip_digital_write(2, 1);
    chip_digital_write(3, 0);
    chip_delay(500);
    stop();
}

function left(): void {
    chip_digital_write(0, 1);
    chip_digital_write(1, 1);
    chip_digital_write(2, 1);
    chip_digital_write(3, 0);
    chip_delay(500);
    stop();
}

function right(): void {
    chip_digital_write(0, 1);
    chip_digital_write(1, 0);
    chip_digital_write(2, 1);
    chip_digital_write(3, 1);
    chip_delay(500);
    stop();
}

export function main(): void {
    chip_pin_mode(0, PinMode.Output);
    chip_pin_mode(1, PinMode.Output);
    chip_pin_mode(2, PinMode.Output);
    chip_pin_mode(3, PinMode.Output);
    chip_pin_mode(4, PinMode.Output);
    chip_pin_mode(10, PinMode.Output); // Led

    chip_digital_write(10, 0);
    chip_delay(5000);

    ble_enable(String.UTF8.encode("WaaRover", true), String.UTF8.byteLength("WaaRover", true));

    const service = ble_service_create(serviceUuid(), 16);
    const command = ble_characteristic_create(
        service, commandUuid(), 16,
        CHRC_WRITE | CHRC_WRITE_NO_RESP, PERM_WRITE);
    ble_advertise_start();

    chip_digital_write(10, 1); // Led on once advertising, for visual confirmation

    // Motor driver is asleep by default, only wake it once BLE is ready.
    chip_digital_write(4, 1);
    stop();

    const bufSize = 20;
    const buf = new ArrayBuffer(bufSize);
    let wasConnected = false;
    while (true) {
        const isConnected = ble_connected();
        if (wasConnected && !isConnected) {
            ble_advertise_start(); // resume advertising after a disconnect
        }
        wasConnected = isConnected;

        if (ble_characteristic_available(command) == 1) {
            const len = ble_characteristic_read(command, buf, bufSize);
            const cmd = String.UTF8.decodeUnsafe(changetype<usize>(buf), len);
            if (cmd.startsWith("forward")) {
                forward();
            } else if (cmd.startsWith("left")) {
                left();
            } else if (cmd.startsWith("right")) {
                right();
            }
        }
        chip_delay(50);
    }
}