i2c Write Register

Write a number value to a device register at an address on the I2C bus.

pins.i2cWriteRegister(0, 0, 0)

Devices connected to an I2C bus will often have registers where data values are set as status or action requests. Although the device is accessed at a single address, it can have multiple registers. Each register has an index so a register write operation can put the data value in the correct place. Registers are like mailslots at a post office that hold a single number value.

Parameters

• address: a number between 8 and 123 that is the address of a chip on the I2C bus.
• register: a number that is the index of the device register to write to.
• value: a number to write to the I2C bus. It’s size (number of bytes) depends on what you say in valueFormat.
• valueFormat: An optional format specifier for the number you will write to the register, like: UInt16LE. The default is UInt8LE.

Example

Write an output value to the conversion register of a digital to analog converter (DAC). The DAC is connected to the I2C bus at address 23 and the conversion register is at index 1.

let DAC = 23
let register = 1 
let dacData = 178
pins.i2cWriteRegister(DAC, register, dacData)

See also

i2c read register i2c write number