Improvements for the AVR DDS Signal Generator V2.0 Project http://www.scienceprog.com/avr-dds-signal-generator-v20/
Changes:
- Synchronization pulse of HS-output on start of sequence or for each period
- Sweep. Start, stop frequency and step are configurable.
- Additional 'options' menu
- Off-state is configurable
- PWM with configurable duty on the HS and analog outputs
- Modify frequency on-the-fly
- Persist all settings
- Maximal frequency increased to 250 kHz
- Frequency resolution is 0.001 Hz
- Speed-up the noise (~x50)
- Calibration of frequency
- One-pulse mode with configurable length on the HS and analog outputs
- Start trigger with configurable delay
- Exact-frequency and minimal-jitter modes
Hardware modification, see circuit for details:
- the RESET button is disconnected from pin 9 and connected to pin 20
- 4 diodes (e.g. 1N4148) are added from pin 3 to buttons RESET, UP, LEFT and DOWN