There are many Cortex-M based platforms in the world. No single tool supports all of them. Most debuggers are written in C and then customized with a scripting language. E.g. TCL in openocd. PyCS is written in Python and customized using Python.
There are multiple levels of customization:
- Cortex-M Options. M0, M0+, M1, M3, M4, M7, number of interrupts, priority bits, etc.
- Vendor Chip Options. cpu core, peripherals, memories, speeds, etc.
- Target Board. SoC chip, external peripherals, gpio assignments, etc.
The idea is to have as much common code as possible.
The vendor directory contains the code that takes general Cortex-M functionality and customizes it to match the specification of a particular vendor chip.
- Cortex-M core: core type, number of interrupts, priority levels, fpu, scb, etc
- SVD file: to provide decode of the peripheral registers
- Memory: flash and ram regions
- etc.
E.g. ./vendor/nordic/nordic.py
The vendor directory also contains vendor specific drivers. These are generally for things like gpio or flash access.
The target directory contains <name>.py files where <name> is the name of the target.
The target files specifies which chip is being used and provide target specific customization.
- gpio naming
- external devices
- default debug interface
- etc.
E.g. ./target/mb997c.py
- If it's in the vendor datasheet it belongs in the vendor directory.
- If it's on the schematic it belongs in the target file.