Summary of MCP4725 DAC AVR ATmega library
The article discusses the MCP4725, a cost-effective 12-bit single-channel DAC with onboard EEPROM, controlled via I2C. The author uses the ATmega8 microcontroller with an embedded I2C interface and employs Peter Fleury's I2C library to drive up to eight MCP4725 devices by setting their addresses via hardware selectors. The DAC output voltage ranges between 2.7V and 5.5V with a 25mA current limit, extendable with opamps and power transistors. The project, tested on an ATmega8 at 8MHz, includes example code to facilitate library use.
Parts used in the MCP4725 DAC AVR ATmega project:
- MCP4725 DAC (12-bit, single-channel with EEPROM)
- ATmega8 microcontroller
- Opamp (optional, for higher current/voltage output)
- Power transistors (optional, for higher current/voltage output)
- Hardware pulldown selectors (for I2C address selection)
The MCP4725 DAC is a pretty common and cheap single channel 12 bit buffered voltage DAC, it also has an onboard EEPROM.
To drive this chip we can use I2C interface.
The ATmega8 used for my implementation has an embedded I2C interface, so we just can use that interface.
The selected I2C library is the one proposed by Peter Fleury, you can find it here: http://homepage.hispeed.ch/peterfleury/avr-software.html
To library provides simple functions to set the output channel of the IC by using raw value or a voltage value.
The voltage output of this chip is limited by his voltage input, that is 2.7v to 5.5v, and the current allowed at the output pin is 25mA.
If you need more current, or more voltage, you can use a combination of opamp and power transistors.
Up to 8 MCP4725 can be driven using this library, the IC address has to be selected using the hardware pulldown selector.
This project has been developed and tested on an ATmega8 running at 8Mhz.
An example program is provided in order to help the library usage.
Code
Read More Detail:MCP4725 DAC AVR ATmega library
