crossBuild ARM target binaries on ARM host

... building STM32F10x (ARM Cortex-M3) sources on WM8505 (ARM9) host.

The Debian installation on my WM8505-based tablet already includes "build-essential" package (gcc, binutils, make, etc.) but, unfortunately, no "multilib" package available yet for debian armel =( . So I have to built my own bare-metal toolchain using croostool-ng. Using this config file, I was able to built this toolchain arm-none-eabi-4.6-armv5.tar.gz (just extract this archive to install). It took almost 20 hrs to finish on WM8505 ( at 300MHz with 128MB RAM ).


For testing the toolchain, I have chosen this STM32F103RB FreeRTOS demo (4 tasks example) sources since it requires "newlib" functions to build completely.

# export CROSS_COMPILE=/path/to/arm-none-eabi/bin/arm-none-eabi-
# make -s clean all
# make program

Also, STM32Loader also works properly on my host machine since it already has python-serial installed. Using "/dev/ttyWMT0" serial port* to transfer the binary using STM32's uart bootloader:

   * USB-to-Serial adapters (e.g. FT232 and PL2303 based) will also work.

For serial-port monitor, I'm using "minicom" already installed on my Debian. Below is the expected result of the STM32 FreeRTOS demo:

Debian Wheezy on WM8505

Installing Debian-Wheezy on microSD card is just simply extracting the two gzip archives into two separate partitions (see below).

$ sudo tar xzpvf wm8505-debian-wheezy-lxde.tar.gz -C /media/extpart/ ; sync
$ sudo tar xzpvf wm8505-kernel-3.0-fatpart.tar.gz -C /media/fatpart/ ; sync

At least 1GB card is needed for the installation, 2GB recommended. The first partition should be a FAT32 (or FAT16) where the "script" folder, containing the "scriptcmd" and "uImage" (linux kernel image) files, is located.The second partition should be an ext2 (or ext4) partition where the root file system will be extracted. Visit these sites for more references: projectgus.com, devio.us , cheap-hack.com.

username: root
password: root

* initial installation using debootstrap
* with minimal LXDE, dillo, build-essential, python, minicom, etc.
* wi-fi / ethernet working ; touchscreen NOT working

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side note:

Recovering "wload" and "u-boot"  without a flash programmer.
However, this procedure needs an already working SPI Flash chip.
( I got mine from another unit. )

I soldered them both in a piggy-back connection, except for their #CS pins (pin 1 = chip select). I also soldered a wire on the pin-1 pad on the board and covered it with a kapton tape as an insulation. The other end of the wire is initially connected to the #CS pin of the working chip. The working chip will be only needed for the first boot until we got to u-boot console prompt (needs serial/uart connector).

After getting to the console(i.e press Enter key on the serial console while booting), transfer the #CS wire to the chip that needs to be reprogrammed (use SPDT switch, if needed).

Then, execute these commands (assuming that "wload.bin" and "u-boot.bin" binaries are already saved in the FAT partition of the SD card)

mmcinit

fatload mmc 0 0 wload.bin
erase ffff0000 +10000
cp.b 0 ffff0000 10000

fatload mmc 0 0 u-boot.bin
erase fff80000 +50000
cp.b 0 fff80000 50000

...  here's the serial log for this process.