229 Analog 8bit R2R DAC
229 : Analog 8bit R2R DAC
- Author: Matt Venn
- Description: A simple 8 bit DAC with a sawtooth waveform driver
- GitHub repository
- Open in 3D viewer
- Clock: 0 Hz
- Feedback: ✅ 2
How it works
A simple 8 bit R2R DAC. Driven externally or by an OpenLane generated sawtooth waveform generator.
How to test
Drive externally
Set the external data input high to provide the DAC with external data.
Then drive the 8 inputs and observe the analog output.
Drive with internal sawtooth wave generator
Set the external data input low to enable the sawtooth generator.
A sawtooth wave should be seen on the analog output.
To change the frequency, set the inputs and then raise the 'load divider' input.
External hardware
A multimeter to measure the output voltage on analog pin 0.
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | bit 0 | external data | |
| 1 | bit 1 | load divider | |
| 2 | bit 2 | ||
| 3 | bit 3 | ||
| 4 | bit 4 | ||
| 5 | bit 5 | ||
| 6 | bit 6 | ||
| 7 | bit 7 |
Analog pins
ua | PCB Pin | Internal index | Description |
|---|---|---|---|
| 0 | A4 | 4 | DAC output |
User feedback
- mattvenn👑: Works as expected!
- diferential: sawtooth works, i see ~600 mV at first attempt at 50Khz / 1Mhz clocks Link for more details