Bench power supply reports 3.3V@3mA, +12V@18mA, -12V@53mA. Found and fixed a wiring error. With DAC output near 0V, output of first opamp, unipolar to bipolar shifter, is -1.0V, as intended.
Next step: hook up SPI to microcontroller. I’ll be using an Energy Micro Wonder Gecko (ARM Cortex-M4F) starter kit. I need to write some test firmware to manually adjust the SPI DAC output, using the capacitive sensing slider of the starter kit, and to pulse the analog switch enables using the buttons of the starter kit. The pulse width of the second analog switch needs to be precisely timed, so I’ll use a hardware timer.