Coding guidelines documentation

docs/ARCHITECTURE.md

@@ -21,9 +21,10 @@ As mentioned previously, all core engine control is handled on the Cortex M7, th
 
 ### Input Signals
 The engine provides two key input signals:
-- Crank pulse
+- Crank pulse, triggered every 180 deg
-- Cam pulse
+- Cam pulse, triggered every 720 deg and slightly dephased
 These are both registered using a hardware interrupt using `TIM2` as a low jitter time source.
+These signals can have missing pulses or extra triggers which need to be accounted for.
 
 ### Time Base
 `TIM2` is the main timebase used to control the engine, it provides 4 channels that are used as follows:

docs/CODING.md

@@ -0,0 +1,20 @@
+# NeoECU Firmware Coding Guidelines
+
+## Naming Conventions
+Functions : camelCase
+Variables : python_case
+Constants : UPPER_CASE
+Macros : UPPER_CASE
+Types : python_case_t
+
+## 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.
+
+## 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.