Direct Digital Synthesizer with USB Interface

The USB-DDS project is very useful for amateur radio operators as a reference oscillator sin it generates sine waves from 0 to 40MHz with millihertz resolution under computer control.

The universal USB interface is based on Atmel AVR firmware for controlling DDS chips and universal parallel input/output. It was a modification of the AVR-USB reference project power switch which is properly working and was made to interface the Analog Devices Direct Digital Synthesizer (DDS) chips. Through the host software, any port can be configured and used as logical input or output that widens the possible applications without having to modify the firmware. The USB device has been connected to an AD9850 DDS board since the device on the experimental board using precision ICs were made to flexibly create the port connections.

The in-circuit ISP programming interface is where the gray cable is connected. The interface is connected to the PC parallel port. By using rigid wires, the LED row can be flexibly connected to the ports of MCU which was used for debugging processes during program development. Interfacing to any DDS chip is allowed by writing the firmware in a flexible way.

Rest of the project