adc-dac-baremetal

# ADC and DAC on bare metal ## Contract | Field | Bound contract | |---|---| | Trigger | The task is to sample an analog input, run the ADC continuously into a DMA buffer, calibrate the ADC after reset, or drive a DAC channel on an MCU without a vendor HAL. | | Authority | Read-only: emits register sequences, formulas, and diagnostics to chat; the user pastes them into their firmware. Rollback is not needed because no file is written. No remote mutation. | | Side effect | Chat output only. | | Done | The guidance names the clock enable, pin mode, sampling time, calibration step, trigger, and readout for the target family, and every register bit is cited to the reference manual chapter it comes from. | ## Inputs - Target MCU family and part number (STM32F1, STM32F4, STM32G4, STM32L4, or another family with a reference manual at hand). - The analog pin and ADC channel, from the datasheet pin table. - Sample rate and source impedance of the signal. - Whether readout is polled, interrupt-driven, or DMA circular. - The ADC clock frequency after prescaling, from the clock tree. ## Procedure 1. Enable the ADC and GPIO clocks and put the pin in analog mode. The ADC reads nothing from a pin still in digital input mode. Done when: the RCC enable bit for the ADC bus and the GPIO port are set and `MODER` for the pin reads analog (`11`). 2. Power the ADC on and wait the stabilization time the datasheet gives as `tSTAB`. On STM32F4 this is `ADC_CR2_ADON` followed by a short wait; the...