Dac-Spi

The AD1860 DAC IC is correctly wired and produces a valid analog output. A reference schematic from the early 1990s is used to identify non-critical components, and a full-scale sawtooth waveform (±3 V) is generated on one channel using an Arduino. The hardware setup functions as expected; the remaining task is implementing a correct SPI interface capable of handling 18-bit transfers.

Several methods for generating ±5 V rails were evaluated, ranging from dual wall warts to regulator-based and buck-boost solutions, with stability, noise, and grounding complexity as the main trade-offs. The most practical approach for the DAC setup proved to be regulator-based supplies, while more complex configurations offered little benefit and higher power consumption.