Convert stm AnalogOutput to use DAC

[BlakeFreer]

STM32 currently produces an "analog output voltage" by controlling the duty cycle of a PWM peripheral. However, stm32 has DAC peripherals. We should use these instead.

EDIT: We should have two AnalogOutput implementations in mcal/stm32 - one for AnalogOutputDAC and AnalogOutputPWM, the latter is the one we already use. Both should be subclasses of the shared::periph::AnalogOutput. Then, each project has the choice of using PWM or DAC to simulate an analog signal, but the public interface is the same.

See the datasheet section 16

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Task

1. Rename the existing stm32 AnalogOutput class (and file) to AnalogOutputPWM. Apply this to all projects where it's used. You can ignore the debug/ projects
2. Create a new file & class AnalogOutputDAC. Follow the structure of the other peripherals.
3. Implement the SetVoltage() function using DAC instead of PWM.

Testing

1. Create a project Demo/AnalogDAC.
2. In main(), use a DAC to create an interesting signal (ex sine / sawtooth wave) which shows you can control the voltage.

   Between each voltage level, add a couple milliseconds of delay. See DelayMS() in the Demo/Blink project

3. Create an stm32 platform. Look at other projects for the structure.
4. Open the STM32CubeMX program and start a new project for your board. Save the project as AnalogDAC/platforms/stm32/cubemx/board_config.ioc
5. Set up a DAC pin.
6. In the "Project Manager" tab of CubeMX, choose these settings
   • Project Structure: Basic
   • Toolchain: CMake
   • Check "Do not generate main()`
   • Code Generation Tab:
     • Select "Generate separate .c and .h files"

Build the project from racecar/firmware/ with

make PROJECT=Demo/AnalogDAC PLATFORM=stm32

Verify the signal on an oscilloscope

[BlakeFreer]

This is low priority since none of our ECUs currently use AnalogOutput.

It is a good task through for someone who wants to write low-level code for the stm