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https://github.com/alejandroherr/i2c-bus-promised
Bus and Device classes for i2c-bus, with promised functions.
https://github.com/alejandroherr/i2c-bus-promised
i2c i2c-bus i2c-device i2c-display i2c-interface i2c-master i2c-sensors promise-functions
Last synced: 4 days ago
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Bus and Device classes for i2c-bus, with promised functions.
- Host: GitHub
- URL: https://github.com/alejandroherr/i2c-bus-promised
- Owner: AlejandroHerr
- License: mit
- Created: 2018-01-21T10:39:34.000Z (almost 7 years ago)
- Default Branch: master
- Last Pushed: 2019-04-03T08:28:11.000Z (over 5 years ago)
- Last Synced: 2024-12-12T14:40:46.022Z (10 days ago)
- Topics: i2c, i2c-bus, i2c-device, i2c-display, i2c-interface, i2c-master, i2c-sensors, promise-functions
- Language: JavaScript
- Homepage:
- Size: 495 KB
- Stars: 1
- Watchers: 3
- Forks: 1
- Open Issues: 14
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
Awesome Lists containing this project
README
# i2c-bus-promised [](https://circleci.com/gh/AlejandroHerr/i2c-bus-promised) [](https://greenkeeper.io/)
[](https://david-dm.org/AlejandroHerr/i2c-bus-promised/master) [](https://david-dm.org/AlejandroHerr/i2c-bus-promised/master#info=devDependencies)
Bus and Device classes for [i2c-bus](https://github.com/fivdi/i2c-bus), with promised functions.
## Installation
```sh
npm install --save i2c-bus-promised
```
## Usage
There's two main class exports in this library: `Bus` and `Device`.
`Bus` class wraps original `i2c-bus` methods and returns them promised, to make more comofrtable to work with them. The calls are queued to avoid blocking calls to the i2c bus.
`Device` class abstracts an `i2c` device.The class is initialised with two arguments, `bus` and `device address`. Internally it will call the reciprocal methods on the bus object with it's address.
```js
// @flow
/* eslint-disable no-console */
import { Bus, Device } from '../src';
import type { AddrType, WordType } from '../src/types';
const main = async () => {
const bus = new Bus();
await bus.open();
// Print bus info
await Promise.all([
bus.i2cFuncs().then((funcs: {[string]: number}) => console.log(JSON.stringify(funcs, null, 2))),
bus.scan().then((devices: Array) => console.log(JSON.stringify(devices, null, 2))),
]);
// Initizalize devices
const weatherSensor = new Device(bus, 0x77);
const lightSensor = new Device(bus, 0x1d);
await weatherSensor.writeByte(0x23, 0b1 | 0b100);
await lightSensor.writeByte(0x25, 0x0f);
return Promise.all([
weatherSensor.readWord(0x50),
weatherSensor.readWord(0x52),
lightSensor.readWord(0x30),
])
.then(([temperature, pressure, light]: Array) => {
console.log(`The temperature is ${temperature}`);
console.log(`The pressure is ${pressure}`);
console.log(`The light is ${light}`);
});
};
main()
.then(() => process.exit(0))
.catch((error: Error) => {
console.error(error.message);
process.exit(1);
});
```
> File [./examples/usage.js](./examples/usage.js)
For more information, consult the [API docs](https://github.com/AlejandroHerr/i2c-bus-promised/blob/master/API.md)
### Extending Device
However, you can also extend the `Device` to work with your i2c devices:
```js
// @flow
/* eslint-disable no-console */
import { Bus, Device } from '../src';
import type { ByteType, WordType } from '../src/types';
class WeatherSensor extends Device {
constructor(bus: Bus) {
super(bus, 0x72);
}
writeConfig(config: ByteType) {
return this.writeByte(0x24, config);
}
readTemperature() {
return this.readWord(0x50);
}
readPressure() {
return this.readWord(0x52);
}
}
const main = async () => {
const bus = new Bus();
const weatherSensor = new WeatherSensor(bus);
await bus.open();
await weatherSensor.writeConfig(0b1 | 0b100);
return Promise.all([
weatherSensor.readTemperature(),
weatherSensor.readPressure(),
])
.then(([temperature, pressure]: Array) => {
console.log(`The temperature is ${temperature}°C`);
console.log(`The pressure is ${pressure}Pa`);
});
};
main()
.then(() => process.exit(0))
.catch((error: Error) => {
console.error(error.message);
process.exit(1);
});
```
> File [./examples/extendingDevice.js](./examples/extendingDevice.js)
For more information, consult the [API docs](https://github.com/AlejandroHerr/i2c-bus-promised/blob/master/API.md#device)
## Tests
To run the tests just type:
```bash
yarn test
```
However it is recomended to run the `e2e` tests to ensure that everything works well.
```bash
BUS_NUMBER=1 yarn test:e2e
```
### mock/createI2cBus
`createI2cBus` is a helper bus to be able to test your code using the library, and ensure that your code is doing what you want.
```js
import { Bus } from '../src';
const BUS_NUMBER = 1;
jest.mock('i2c-bus', () => {
const createI2cBus = require('../src/mock/createI2cBus').default; // eslint-disable-line global-require
return createI2cBus({
busNumber: 1,
devices: {
0x0f: Buffer.from(Array.from(Array(0xff).keys()).reverse()),
0xf0: Buffer.from(Array.from(Array(0xff).keys())),
},
funcs: {
read: 0x01,
write: 0x02,
},
});
});
const setup = async (busNumber) => {
const bus = new Bus(busNumber);
await bus.open();
return {
bus,
addToQueue: jest.spyOn(bus, 'addToQueue'),
physicalBus: bus.bus.physicalBus,
};
};
describe('Bus', () => {
describe('i2cFuncs', () => {
it('calls the i2cBus function through the promise queue', async () => {
const { bus, addToQueue, physicalBus } = await setup(BUS_NUMBER);
const result = await bus.i2cFuncs();
expect(addToQueue).toHaveBeenCalledWith('i2cFuncsAsync');
expect(result).toBe(physicalBus.funcs);
});
});
describe('scan', () => {
it('calls the i2cBus function through the promise queue', async () => {
const { bus, addToQueue, physicalBus } = await setup(BUS_NUMBER);
const result = await bus.scan();
expect(addToQueue).toHaveBeenCalledWith('scanAsync');
expect(result).toEqual(Object.keys(physicalBus.devices).map(addr => parseInt(addr, 10)));
});
});
});
```
> File [./examples/tests.js](./examples/tests.js)
Be aware that you're working with a real device, the tests won't be much meaningful. And many things can fail _IRL_. It's always recommendable to write `e2e` tests to run in a real device.
## Dependencies
- [bluebird](https://github.com/petkaantonov/bluebird): Full featured Promises/A+ implementation with exceptionally good performance
- [i2c-bus](https://github.com/fivdi/i2c-bus): I2C serial bus access with Node.js
- [p-queue](undefined): Promise queue with concurrency control
## Documentation
[Read the API](https://github.com/AlejandroHerr/i2c-bus-promised/blob/master/API.md)
## License
MIT © Alejandro Hernandez