First doc writeup

docs/CODING.md

@@ -1,20 +1,27 @@
 # NeoECU Firmware Coding Guidelines
 
-## Naming Conventions
-Functions : camelCase
-Variables : python_case
-Constants : UPPER_CASE
-Macros : UPPER_CASE
-Types : python_case_t
+These rules apply to the `CM7` engine-control firmware.
 
-## Performance Standard
-Don't use heap at all if possible avoid mallocs at all cost.
-Don't make heavy computation in ISR delegate everything to a task that you'll wake.
-Don't copy big chunks of memory, use pointers if you need to read a buffer, even if simply passing the buffer as a parameter compiles it will have huge overhead.
+## Style
 
-## Readability Standard
-Avoid more than one layer of pointer indirection if possible.
-Don't use void* they are unclear and make mistakes more likely.
-Avoid magic numbers and indexes, use macros and constants to define them clearly.
-Define all macros in macros.h and all global variables and constants in glocal_state.h.
-Use one c file per feature, avoid big monoliths that become hard to jump around.
+- Functions: `camelCase`
+- Variables: `python_case`
+- Constants and macros: `UPPER_CASE`
+- Types: `python_case_t`
+
+## Real-Time Code
+
+- Do not allocate from the heap in the engine-control path.
+- Prefer static task, buffer, and control-structure allocation.
+- Keep ISRs short: capture data, update the minimum state, wake a task, return.
+- Keep heavy validation, filtering, and scheduling logic in task context.
+- Avoid avoidable copies, indirection, and generic `void *` plumbing.
+
+## Structure
+
+- Keep one source file per feature or subsystem where practical.
+- Put shared engine state in `global_state.h`.
+- Put shared helper macros in `macros.h`.
+- Prefer explicit state machines over implicit control flow.
+- Make ISR-to-task ownership obvious from names and file placement.
+- Use named constants and enums instead of magic numbers.