Maple JTAG How To

This is a page about using JTAG with Maple - JTAG will allow you to use a debugger program like GDB to debug programs running on the Maple. You can also use the JTAG adapter to re-flash (re-install) the bootloader in case you "brick" the board and can't install programs on it via the bootloader.

JTAG Debugger

You need a piece of hardware called a JTAG debugger to manage the connection and debugging of the Maple. These plug into your computer via USB and into the Maple via its JTAG port.

• Olimex ARM-USB-OCD - only this debugger is known to work. Olimex's ARM-USB-TINY is known not to work.
• ARM-USB-OCD at Sparkfun

If you know of other JTAG debuggers that are known to work, add them here.

JTAG Adapter

Maple's 8-pin JTAG port is non-standard, so you need an adapter circuit to go between the ARM 20-pin connector and the Maple 8-pin connector.

• Maple JTAG adapter circuit and board layout - the one in Maple's source tree may work, but has extra resistors and other errors. This circuit is known to work.
• Circuit diagram
• picture of PCB design

OpenOCD

OpenOCD is a program that can talk with the JTAG debugger. You can give commands to it directly, or you can configure GDB to use it to control your Maple board.

Download the latest version of OpenOCD, build it, and install it. Then you can use Maple's build tools (Make) to run the JTAG debugger, or run it standalone so you can connect via another program.

You will need to edit the OpenOCD configuration files to make them work with recent OpenOCD versions. Make the following changes:

• File support/openocd/run.cfg:
  • Add at the beginning of the file

#daemon configuration
telnet_port 4444
gdb_port 3333

Replace this line:

-flash bank stm32x 0x08000000 0x00020000 0 0 $_TARGETNAME

with this:

set _FLASHNAME $_CHIPNAME.flash
flash bank $_FLASHNAME stm32x 0x08000000 0x00020000 0 0 $_TARGETNAME

Eclipse C/C++

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