DAC7574

Arduino library for DAC7574 quad 12-bit digital to analog converter with I2C interface

TI Part info

Simple Usage

The simplest use case is when each channel is individually programmed using dac.setData(v, channel). This can be seen in the example dac7574_nano_test.

Declare an instance of the part using DAC7574 dac. Initialize the default TwoWire instance Wire by calling Wire.begin() and optionally setting it's speed by calling Wire.setClock(400000L). Use dac.begin(address) to initialize the instance to use the I2C address and the default I2C channel, Wire. Note that only two bits of address corresponding to the settings of the A0, A1 pins for the part are required (i.e., address is in 0..3). The remaining 5 bits of the 7-bit I2C address are constant and are provided by the library.

Synchronized Channel Setting

The dac7574_nano_sync example shows all four channels programmed synchronously using the dac.setDataAll(v0, v1, v2, v3) so that their outputs change simultaneously.

You can also do this using the dac.setBuffer(v, channel) to store the values of 3 channels individually to buffers in the part first and then using the dac.setDataSync9v, channel) function to set the value of the 4th channel and simultaneouly loading the previously programmed buffer values for the remaining 3 channels.

Synchronized Setting on Multiple DAC7574 parts

The dac7574_dual_nano example shows how 2 DAC7574 parts on the same I2C bus can be programmed synchronously so that all 8 values change simultaneouly. This is done using dacx.setBuffer(v, channel) for each of the 4 channels on both parts to set their buffer values, and then using dac0.setBcstSync() to broadcast the synchronizatoin command to both parts. Note that you only need to call setBcstSync() on any one of the parts.

Using Other Wire Channels

The Arduino Wire library declares a global instance of TwoWire named Wire and this library uses that by default. But if you plan to use a different instance of TwoWire, you can pass that instance in when you call dac.begin(address, twire).

For example, to use the 2nd I2C bus on a STM32F411-based "Black Pill" board, use:

TwoWire Wire2(PB3, PB10); // SDA2 is PB3, SCL2 is PB10

And in setup() call:

Wire2.begin();

dac.begin(0, &Wire2); // A1,A0 = 0, can be 0..3