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I2C
The
i2c module supports communication with I2C (Inter-Integrated Circuit) / TWI (Two Wire Interface) devices. Use require('i2c') to access this module.
Class: I2C
An instances of
I2C represents a I2C bus.I2C.MASTER
<number>=0
I2C.SLAVE
<number>=1
new I2C(bus[, options])
bus<number>I2C bus number.options<object>The object of I2C options. Default values are depends on board (Check in a board page).mode<number>I2C mode,I2C.MASTERorI2C.SLAVEmode. Default:I2C.MASTERbaudrate<number>Clock speed (bit/s) for Master mode.scl<number>SCL pin number.sda<number>SDA pin number.
- Returns:
<object>The return value isI2Cobject.
Instances of the
I2C class can be created using the new keyword or by calling i2c.I2C() as a function. A RangeError will be thrown if bus exceeds max bus number.1
// Create the I2C instance with master mode
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const {I2C} = require('i2c');
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// open bus 0 in master mode
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const i2c0 = new I2C(0);
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// read or write ...
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i2c0.close();
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// open bus 1 in master mode, full speed
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const i2c1 = new I2C(1, {mode: I2C.MASTER, baudrate: 400000);
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// read or write ...
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i2c1.close();
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i2c.write(data, address[, timeout[, count]])
data<Uint8Array|string>Data to write.address<number>I2C slave address. (7bit)timeout<number>Timeout in milliseconds. Default:5000.count<number>Indicates how many times to write data. Default:1- Returns:
<number>The number of bytes written,-1if it failed to write or timeout.
This method writes data to the specified address (slave device) and returns the number of bytes written. This method can be called only in master mode.
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const {I2C} = require('i2c');
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const i2c0 = new I2C(0, {baudrate: 50000}); // master mode 50 kbits/s
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// Writes 2 bytes as a Uint8Array
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var array = new Uint8Array([0x6b, 0x00]);
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i2c0.write(array, 0x68);
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// Writes 5 bytes as a string
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i2c0.write('Hello', 0x68);
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i2c0.close();
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i2c.read(length, address[, timeout])
length<number>Data length to read.address<number>I2C slave address. (7bit)timeout<number>Timeout in milliseconds. Default:5000.- Returns:
<Uint8Array>An array buffer having data read,nullif failed to read.
This method read data from the specified address (slave device) and returns an array buffer object. This method can be called only in master mode.
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const {I2C} = require('i2c');
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const i2c0 = new I2C(0);
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// Read 14 bytes from the address 0x68.
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var buf = i2c0.read(14, 0x68);
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if (buf) {
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console.log(data.length); // 14
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console.log(data[0]); // first byte
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}
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i2c0.close();
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i2c.memWrite(data, address, memAddress[, memAddressSize[, timeout[, count]]])
data<Uint8Array|string>Data to write.address<number>I2C slave address. (7bit)memAddress<number>Memory address to write.memAddressSize<number>Size ofmemAddress. Set16whenmemAddressis 16-bit address, or set8ifmemAddressis 8-bit address. Default:8.timeout<number>Timeout in milliseconds. Default:5000.count<number>Indicates how many times to write data. Default:1- Returns:
<number>The number of bytes written,-1if failed to write or timeout.
This method writes data to the memory address in the specified slave device and returns the number of bytes written. This method can be called only in master mode.
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const {I2C} = require('i2c');
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const i2c0 = new I2C(0);
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// Writes 2 bytes at memory address 0x10 of slave 0x68
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var array = new Uint8Array([0x6b, 0x00]);
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i2c0.memWrite(array, 0x68, 0x10);
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i2c0.close();
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i2c.memRead(length, address, memAddress[, memAddressSize[, timeout]])
length<number>Data length to read.address<number>I2C slave address. (7bit)memAddress<number>Memory address to read.memAddressSize<number>Size ofmemAddress. Set16whenmemAddressis 16-bit address, or set8whenmemAddressis 8-bit address. Default:8.timeout<number>Timeout in milliseconds. Default:5000- Returns:
<Uint8Array>A buffer having data read,nullif failed to read.
This method read data at memory address from the specified slave device and returns an array buffer object. This method can be called only in master mode.
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const {I2C} = require('i2c');
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const i2c0 = new I2C(0);
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// Read 14 bytes at memory address 0x0100 from slave 0x68
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var buf = i2c0.memRead(0x0100, 14, 0x68, 1);
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if (buf) {
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console.log(data.length); // 14
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console.log(data[0]); // first byte
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}
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i2c0.close();
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i2c.close()
This method closes the I2C bus.
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const {I2C} = require('i2c');
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const i2c0 = new I2C(0);
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// Write or read from I2C ...
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i2c0.close(); // Close i2c device
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Last modified 1mo ago
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