Programming the Arduino in Eclipse

This is a note on installing the Eclipse Arduino Plugin, specifically on Windows (32-bit), with pointers to archived materiel.

Arduino Due and the Watchdog

A watchdog is used to detect when a system has gone off with the fairies; you have to reset the watchdog timer ("pat the watchdog") every so often or it takes some recovery action. In the case of the Arduino Due, with the ATSAM3X8E MCU, the recovery action is to reset the CPU.

In the ATSAM3X8E (and probably other Atmel MCUs, too), the watchdog timeout defaults to 16 seconds, and the default hardware state is that the watchdog is enabled! (the default in the Atmel Software Framework is to disable the watchdog unless you have defined CONF_BOARD_KEEP_WATCHDOG_AT_INIT).

Arduino Due/Segger J-Link EDU

I’ve been porting my Cortex-based RTS to Arduino Due, using the J-Link JTAG interface (because who can make an RTS without a debugger?). I’ve probably forgotten my initial problems with ST-LINK (an equivalent interface included for free on the STM32F4 board, supported by OSS software), but it seemed a much less trying experience than with Segger.

There are two things with J-Link GDB Server: first, it seems like a bad idea to keep the server alive after a GDB session ends, so start it with -singlerun; and second, you absolutely must issue monitor reset before running your program. If you don’t you’ll end up like I did, scratching my head for three days trying to understand why I was getting a HardFault at the SVC that FreeRTOS uses to kick tasking off.

Building a runtime system for arm-eabi

AdaCore provide a compiler (running on Windows and Linux) targeted to ARM (target arm-eabi) and a runtime system (RTS) supporting the Ravenscar profile.

The public version of the AdaCore Ravenscar RTS is released under the full GPL. It seemed as if it would be a good idea (and fun!) to produce an independent RTS with the GCC Runtime Library Exception (FAQ).

Building GCC 5.1.0 for arm-eabi

These notes describe building GCC 5.1.0 for the Cortex M4 on Mac OS X.

My target board is the STM32M4F29I Discovery.

Building GCC 5.1.0

These notes describe building GCC 5.1.0 for Mac OS X, with Ada, C, C++, Fortran, Objective C, Objective C++, and various GNAT tools.

Relocating GCC

AdaCore's doinstall is an excellent way of installing the compiler where you want to. Unfortunately, GCC 4.9 uses the shared libgcc_s.1.dylib, which has no @rpath-type constructs, and so the compiler executables expect to find libgcc_s.1.dylib in the place it was built for. (Not to mention libstdc++.6.dylib.)