config-wp

Skeleton project for the Rivan embedded configuration management exercise.

The goal of the exercise is to design and implement a configuration management system suitable for our embedded systems. This repository provides the development environment so that work can be done on any machine, run under FreeRTOS (POSIX port), and unit-tested with GoogleTest / GoogleMock.

Layout

.
├── CMakeLists.txt          Root build (FreeRTOS app + tests)
├── cmake/FreeRTOSConfig.h  FreeRTOS kernel config
├── src/
│   ├── main.c              Scheduler bring-up + app task
│   ├── application/        Configuration management code (your work)
│   └── drivers/            Hardware abstractions (storage, etc.)
├── tests/                  GTest / GMock unit tests
├── Dockerfile              Builds + runs the FreeRTOS binary
└── Dockerfile.test         Builds + runs the unit tests

application/ and drivers/ are intentionally minimal - extend them.

Run the application

docker build -t config-wp .
docker run --rm -it config-wp

Run the tests

docker build -f Dockerfile.test -t config-wp-test .
docker run --rm config-wp-test

System-level details + constraints:

• Ultimately will be deployed on STM32Gx w/ FreeRTOS. For demonstration purposes no need to run on target. Running on a host (clang w/ POSIX port of FreeRTOS preferred) is fine.
• Must be relatively simple to port code to a new HW vendor. No need for OS abstraction layer, presume we will continue to use FreeRTOS.
• C or C++, at your discretion
• Must have reasonable test coverage - pref GTest/Gmock

Requirements

• Stores configuration data needed to operate IOs associated with the system
  • DI (name: string(16), ID, debounce time, fault state: hold/0/1…)
  • DO (name,...)
  • TC (name,...)
  • AI (name,...)
  • AO (name,...)
  • PCNT (name,...)
  • PWM (name, period, duty, fault state: hold/off/on…)
• We are considering abiding by the CiA 401 device profile (generic I/O device), so expect these parameters to align pretty well with it. PDF available here after making an account: https://www.can-cia.org/can-knowledge/cia-401-series-i/o-device-profile
  • The profile will require some extension to define counter input and PWM output
• Stores configuration data required for the system to run (e.g. CAN ID, data rate…)
• R/W access to the configuration must be re-entrant / thread safe
• Configuration format must support future extensions and modifications, and configuration must remain forward compatible
• Configuration should be flexible - i.e. some I/Os may be dual/triple function
• Configuration storage must be abstracted for the medium: may be stored on internal flash, external EEPROM etc.
• Configuration must be (relatively) human readable / editable
• Configuration must be modifiable piece-wise or monolithically (i.e. changing config on a per-I/O basis, or as a whole device)
• Manager must be able to detect R/W/input errors and validate inputs