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.
These two binary preparation steps are not strictly necessary as the eCos distribution ships with pre-compiled binaries in the directory loaders/powerpc-mbx relative to the installation root.
Start with a new document - selecting the File->New menu item if necessary to do this.
Choose the Build->Templates menu item, and then select the PowerPC Motorola MBX860/821 hardware.
While still displaying the Build->Templates dialog box, select the “stubs” package template to build a GDB stub. Click OK.
Build eCos using Build->Library.
When the build completes, the image files can be found in the bin/ subdirectory of the install tree. GDB stub ROM images have the prefix “gdb_module”.
Make an empty directory to contain the build tree, and cd into it.
To build a GDB stub ROM image, enter the command:
$ ecosconfig new mbx stubs |
Enter the commands:
$ ecosconfig tree $ make |
When the build completes, the image files can be found in the bin/ subdirectory of the install tree. GDB stub ROM images have the prefix “gdb_module”.
Program the binary image file gdb_module.bin into ROM or FLASH referring to the instructions of your ROM programmer.
Plug the ROM/FLASH into socket XU1 as described near the beginning of this Hardware Setup section.
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 be programmed]
Set jumper 4 to 2-3 [boot EPPC-Bug]
Prepare EPPC-Bug for download:
EPPC-Bug>lo 0 |
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 window.
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 stubs.