The eCos Developer’s Kit package comes with an EPROM
which provides GDB support for the Motorola
PowerPC MBX860 evaluation board. An image of this EPROM is also
provided at loaders/powerpc-mbx/gdbload.bin under
the root of your eCos installation.
The EPROM is installed to socket XU1 on the board. Attention
should be paid to the correct orientation of the EPROM during installation.
Only replace the board"s existing ROM using a proper PLCC
extraction tool, as the socket would otherwise risk getting damaged.
The GDB stub in the EPROM allows communication with GDB using
the serial port at connector SMC1/COM1. The communication
parameters are fixed at 38400 baud, 8 data bits, no parity bit and
1 stop bit (8-N-1). No flow control is employed. Connection to the
host computer should be made using a suitable serial cable.
In order to make the board execute the EPROM that you just
installed (rather than the on-board FLASH memory), it may be necessary
move some links on the board. Specifically, ensure that link J4
is in position 1-2. If in doubt, refer to the MBX documentation
from Motorola, ensuring that Boot Port Size=8 Bits/ROM
for BOOT (CS#7), in their terminology.
This assumes you have EPPC-Bug in the on-board FLASH. This
can be determined by setting up the board according to the below
instructions and powering up the board. The EPPC-Bug prompt should
appear on the SMC1 connector at 9600 baud, 8N1.
Set jumper 3 to 2-3 [allow XU2 FLASH to
At this point the monitor is ready for input. It will not return
the prompt until the file has been downloaded.
Use the terminal emulator’s ASCII download feature
(or a simple clipboard copy/paste operation) to download
the gdb_module.srec data.
Note that on Linux, Minicom’s ASCII download feature seems
to be broken. A workaround is to load the file into Emacs (or another
editor) and copy the full contents to the clipboard. Then press
the mouse paste-button (usually the middle one) over the Minicom
Program the FLASH with the downloaded data:
EPPC-Bug>pflash 40000 60000 fc000000
Switch off the power, and change jumper 4 to 1-2. Turn
on the power again. The board should now boot using the newly programmed