A simple 8 bit R2R DAC. Driven externally or by an OpenLane generated sawtooth waveform generator.
Set the external data input high to provide the DAC with external data.
Then drive the 8 inputs and observe the analog output.
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.
A multimeter to measure the output voltage on analog pin 0.
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | multiplexed data/address bus LSB | (pwm) channel C | (in) **BC1** bus control |
| 1 | multiplexed data/address bus | (pwm) channel B | (in) **BDIR** bus direction |
| 2 | multiplexed data/address bus | (pwm) channel A | (in) **SEL0** clock divider |
| 3 | multiplexed data/address bus | (in) **SEL1** clock divider | |
| 4 | multiplexed data/address bus | ||
| 5 | multiplexed data/address bus | ||
| 6 | multiplexed data/address bus | ||
| 7 | multiplexed data/address bus MSB |
ua | analog | Description |
|---|---|---|
| 0 | 11 | (out) channel C |
| 1 | 6 | (out) channel B |
| 2 | 10 | (out) channel A |