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export const ADDR = {
CTRL: 0xdb96,
OVEN: 0xaa55,
};
export const FUNC = {
// used by oven
O_CONNECT: 0x01,
O_TEMPS: 0x02,
O_READ: 0x03,
O_ACK_WRITE: 0x06,
// used by CTRL
C_PWM_HEAT: 0x08,
C_PWM_COOL: 0x0d,
C_STARTSTOP: 0x10,
C_REQ_READ: 0x11,
C_WRITE: 0x20,
C_ACK_CONNECT: 0xf1,
C_ACK_READ: 0xf2,
};
export const ARG = {
// for STARSTOP, REQUEST_READ
STARTSTOP_START: 0x11,
STARTSTOP_STOP: 0x22,
REQUEST_READ: 0x11,
// for CONNECT / ACK_CONNECT
CONNECT_CONNECTING: 0x0100,
CONNECT_CONNECTED: 0x0200,
// for *_PWM
PWM_ON: 0x44,
PWM_OFF: 0x88,
};
const lookup = (tbl, val) => Object.keys(tbl).find(key => tbl[key] === val);
export class Message {
constructor(buffer) {
this.buf = buffer;
this.view = new DataView(this.buf);
this.data = new DataView(this.buf, 4, this.buf.byteLength - 6);
}
get16(i) { return this.data.getUint16(i, false); }
set16(i, v) { this.data.setUint16(i, v, false); }
get address() { return this.view.getUint16(0, false); }
set address(val) { this.view.setUint16(0, val, false); }
get func() { return this.view.getUint8(2); }
set func(val) { this.view.setUint8(2, val)}
get data_len() { return this.view.getUint8(3); }
set data_len(val) { this.view.setUint8(3, val); }
get length() { return this.buf.byteLength; }
get checksum() { return this.view.getUint16(this.buf.byteLength-2, false); }
set checksum(val) { this.view.setUint16(this.buf.byteLength-2, val, false); }
calculateSum() {
let sum = 0;
for (let i = 0; i < this.length - 2; i++) {
sum += this.view.getUint8(i);
}
return sum & 0xffff;
}
getDataArray() {
return new Uint8Array(this.buf, 4, this.buf.byteLength - 6);
}
toString() {
const address = lookup(ADDR, this.address) ?? "????";
const func = lookup(FUNC, this.func) ?? "?_??";
const data = this.getDataArray();
return `to ${address}: ${func.substr(2)} [${data}]`;
}
static from8(addr, func, data) {
const len = 2 + 2 + data.length + 2;
const msg = new Message(new ArrayBuffer(len));
msg.address = addr;
msg.func = func;
msg.data_len = data.length;
for (let i = 0; i < data.length; i++) {
msg.data.setUint8(i, data[i]);
}
msg.checksum = msg.calculateSum();
return msg;
}
static from16(addr, func, data) {
const len = 2 + 2 + 2*data.length + 2;
const msg = new Message(new ArrayBuffer(len));
msg.address = addr;
msg.func = func;
msg.data_len = 2*data.length;
for (let i = 0; i < data.length; i++) {
msg.data.setUint16(2*i, data[i], false);
}
msg.checksum = msg.calculateSum();
return msg;
}
static empty(addr, func, data_len) {
const len = 2 + 2 + 2*data_len + 2;
const msg = new Message(new ArrayBuffer(len));
msg.address = addr;
msg.func = func;
msg.data_len = data_len;
return msg;
}
static tryParse(buffer) {
if (buffer.length < 4 + 2) return;
const data_len = buffer[3];
if (buffer.length < 4 + data_len + 2) return;
const msg = new Message(buffer.slice(0, 4 + data_len + 2).buffer);
if (msg.calculateSum() !== msg.checksum) {
throw new Error(`checksum mismatch: expected ${hex(msg.checksum)} but calculated ${hex(msg.calculateSum())}`);
}
return msg;
};
}
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