DDS Signal Generator Using AVR

The project is a second version of the AVR signal generator where it uses a single sided PCB for simplification while containing both offset and amplitude controls.

This version of DDS signal generator is firmware based which uses slightly modified algorithm adapted to AVR-DCC program. It consists of two outputs where one is for the DDS signal and another for high speed square signal with 1.8MHz frequency that will be used for reliving microcontrollers with wrong fuse settings. The high speed signal is a direct output from ATmega16 OC1A pin. All other signals that are generated via R2R resistor network uses the DDS output and is adjusted through LM358N offset and amplitude regulating circuits. Two potentiometers are used to regulate the offset and amplitude.

The LCD menu is used to view all actions and can be controlled with 5 buttons placed next to LCD module. For browsing menu, the up and down buttons are used while for changing the frequency value, the right and left arrow buttons are used. The signal generating starts when the middle button is pressed. It will stop the signal generator operation by pressing the middle button again.

Rest of the project