To interface 8-bit DAC with AVR microcontroller ATMega32 and generate different waveforms like Square Wave, Sine Wave, Triangular Wave, Staircase Wave and Saw-tooth Wave.
· AVR Development Board
· ADC – DAC card
· Digital Storage Oscilloscope (DSO)
· Power Supply
· Connecting Wires
· CRO Probes
· General purpose PCB
· AVR Microcontroller – ATMega32
· 8-bit – DAC0808
· Operational Amplifier – LM741
· Push Button Switches
· Resistors and Capacitors
To generate different Analog waveforms using AVR microcontroller it is required to interface a DAC that will convert the Digital inputs given by microcontroller into corresponding Analog outputs and thus it generates different analog waveforms. The DAC output is current equivalent of digital input. So to convert it in to voltage a current to voltage converter is required. This current to voltage converter is build using Op-Amp LM741.
PORTA is used as input and PORTC is used as output. Four push button switches are connected to PORTA pins PA0 to PA3. Rest four pins PA4 to PA7 are connected to Vcc. PORTC is connected to input pins A1 to A8 ofDAC0808. Vref pin of DAC0808 is connected to Vcc through 5 K Resistor to generate require output current Iref. –Vref pin is connected to ground through 5 K Resistor. The current output Iout of DAC0808 is connected to inverting input of Op-Amp LM741 that is used as current to voltage converter. A 5 K load Resistor is connected in the output of LM741 to generate voltage output.
Complete circuit requires 3 different supplies +5 V, +12 V and -12 V. ATMega32 and DAC0808 require +5 V. DAC0808 require -12V for its Vee supply input. LM741 requires +12 V and -12 V for biasing. For detailed Circuit Diagram click on Circuit Diagram Tab
Here is the snap of circuit built using AVR Development Board, ADC-DAC card and Op-Amp
For more detail: DIY – Waveform Generator using AVR Microcontroller