Known Issues

This page documents known issues, limitations, and workarounds for the AddVantage PPG firmware and test tools.

Firmware Issues

WDOG-001: Watchdog Must Be Disabled Immediately

Severity: Critical

Description: The SKEAZ128 watchdog timer must be disabled within 256 bus clock cycles after reset. If any code executes before the watchdog unlock sequence, the device will boot loop.

Symptoms:

  • Device continuously resets

  • Multiple version strings in UART output

  • “Boot loop detected” in test harness

Root Cause: The default ARM startup code (__thumb_startup from EWL) performs C runtime initialization before calling main(). This takes longer than the watchdog timeout window.

Solution: A custom reset handler in startup_wdog.S disables the watchdog immediately:

Reset_Handler:
    ldr r0, =0x40052000   ; WDOG base
    ldr r1, =0x20C5       ; Unlock key 1
    ldr r2, =0x28D9       ; Unlock key 2
    strh r1, [r0, #0x0E]  ; Write to WDOG_UNLOCK
    strh r2, [r0, #0x0E]  ; Complete unlock
    movs r1, #0x00
    strh r1, [r0, #0x00]  ; Disable WDOG via WDOG_CS1

Status: Fixed in v3.2.7

CAN-001: Oil Temperature Not Reliable from Simulator

Severity: Low

Description: The oil temperature field (from PGN ET1 bytes 2-3) occasionally reads -40°C or other incorrect values when using the CAN simulator test box.

Symptoms:

  • Oil temp shows -40°C or fluctuates wildly

  • Only occurs with test equipment, not live engines

Root Cause: The CAN simulator test box does not correctly simulate the 16-bit oil temperature field in the ET1 message. The coolant temperature (byte 0) works correctly.

Workaround: The firmware uses coolant temperature for all thermal logic, so this does not affect operation. The CAN viewer and validation tools ignore oil temperature.

Status: Known limitation of test equipment (not a firmware bug)

FLASH-001: Limited Erase Cycles

Severity: Low

Description: Flash memory has approximately 10,000 erase cycles per sector. Frequent configuration changes could wear out the flash.

Symptoms:

  • Configuration fails to save

  • Values revert after power cycle

Workaround:

  • Avoid frequent configuration changes

  • Batch changes and save once

  • For development, consider external EEPROM

Status: Hardware limitation

Test Harness Issues

TH-002: Serial Port Auto-Detection May Choose Wrong Port

Severity: Low

Description: On systems with multiple USB-serial adapters, the auto-detection may choose the wrong port.

Symptoms:

  • “No output received” when correct hardware is connected

  • Data from wrong device

Workaround: Explicitly specify the port:

python tools/test_harness.py --hex build/addvantage3.hex --port /dev/cu.usbmodem55014603

Status: Won’t fix (by design - auto-detect is a convenience feature)

TH-003: PCAN Library Path on macOS

Severity: Medium

Description: The PCAN library (libPCBUSB.dylib) must be in ~/lib on macOS. If not found, CAN validation fails.

Symptoms:

  • “CAN validation: python-can or PCAN library not available”

  • Import errors when running can_capture.py

Workaround: Copy the library to the expected location:

mkdir -p ~/lib
cp /path/to/libPCBUSB.dylib ~/lib/

The tools set DYLD_LIBRARY_PATH automatically.

Status: Documented

Build Issues

BUILD-001: CodeWarrior Legacy Build Deprecated

Severity: Info

Description: The original CodeWarrior build system is deprecated. Use the CMake build instead.

Symptoms:

  • Make errors in DEBUG directory

  • Missing ProcessorExpert files

Solution: Use CMake build:

mkdir build && cd build
cmake -G Ninja -DCMAKE_TOOLCHAIN_FILE=../arm-gcc-toolchain.cmake ..
ninja

Status: CMake build is the supported method

BUILD-002: ARM Toolchain Version Sensitivity

Severity: Low

Description: Some older ARM GCC versions produce different code sizes or may have bugs in Cortex-M0+ codegen.

Symptoms:

  • Warning messages during compilation

  • Slightly different binary output

Workaround: Use ARM GCC 10.3 or newer. The official ARM download is recommended over distro packages.

Status: Documented

Documentation Issues

DOC-001: Some C Functions Lack Doxygen Comments

Severity: Low

Description: Not all C functions have Doxygen-style documentation comments. API reference may be incomplete.

Affected Files:

  • Events.c - Partial coverage

  • can.c - Minimal comments

  • adc.c - Minimal comments

Status: Documentation improvement in progress

Reporting New Issues

To report a new issue:

  1. Check this page for existing known issues

  2. Reproduce the issue with latest firmware

  3. Collect relevant logs (UART output, test harness output)

  4. Open an issue at: https://github.com/[repo]/issues

Include:

  • Firmware version

  • Hardware configuration

  • Steps to reproduce

  • Expected vs actual behavior

  • Relevant log output