node-web-i2c/index.js
2019-10-18 03:23:29 +09:00

66 lines
1.9 KiB
JavaScript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const i2c_bus_1 = require("i2c-bus");
const I2CPortMapSizeMax = 32;
const Uint16Max = 65535;
function parseUint16(string) {
const n = Number.parseInt(string, 10);
if (0 <= n && n <= Uint16Max)
return n;
else
throw new RangeError(`Must be between 0 and ${Uint16Max}.`);
}
class I2CAccess {
constructor(ports) {
this._ports = ports == null ? new I2CPortMap() : ports;
}
get ports() {
return this._ports;
}
}
exports.I2CAccess = I2CAccess;
/**
* Different from Web GPIO API specification.
*/
class I2CPortMap extends Map {
getByName(portName) {
const matches = /^i2c-(\d+)$/.exec(portName);
return matches == null ? undefined : this.get(parseUint16(matches[1]));
}
}
exports.I2CPortMap = I2CPortMap;
class I2CPort {
constructor(portNumber) {
this._portNumber = parseUint16(portNumber.toString());
}
get portNumber() {
return this._portNumber;
}
get portName() {
return `i2c-${this.portNumber}`;
}
async open(slaveAddress) {
const bus = await i2c_bus_1.openPromisified(this.portNumber).catch(error => {
throw new OperationError(error);
});
return {
slaveAddress,
read8: cmd => bus.readByte(slaveAddress, cmd),
read16: cmd => bus.readWord(slaveAddress, cmd),
write8: (cmd, byte) => bus.writeByte(slaveAddress, cmd, byte),
write16: (cmd, word) => bus.writeWord(slaveAddress, cmd, word)
};
}
}
exports.I2CPort = I2CPort;
class OperationError extends Error {
}
exports.OperationError = OperationError;
async function requestI2CAccess() {
const ports = new I2CPortMap([...Array(I2CPortMapSizeMax).keys()].map(portNumber => [
portNumber,
new I2CPort(portNumber)
]));
return new I2CAccess(ports);
}
exports.requestI2CAccess = requestI2CAccess;