TX49 Hardware Setup

The eCos installation CD contains a copy of the eCos GDB stubs in SREC format which must be programmed into the board’s FLASH memory.

Preparing the GDB stubs

These stub preparation steps are not strictly necessary as the eCos distribution ships with pre-compiled stubs in the directory loaders/tx49-ref4955 relative to the installation root.

Installing GDB stubs into FLASH

Boot into the board’s firmware in little-endian mode:

Set the switches like this:

SW1: 10000000 (first lever up, the rest down) SW2: 10000010

Connect serial cable on the lower connector, configure terminal emulator for 38400, 8-N-1.

When booting the board, you should get this prompt:

HCP5 rev 0.9B .    

Select o (option), a (FLASH) and b (boot write). You should see this:

Boot ROM Write   
ROM address-ffffffffbd000000, Boot Bus-[32bit]  
ID2 0 4 ffffffffa002ad40  
zzz SS-40000 IV-1 CS-20000 CC-2   
Flash ROM-[28F640J5], [16bit chip] * 2 * 1
Block size-00040000  count-64  
ROM adr ffffffffbd000000-ffffffffbe000000  mask-00fc0000
Send Srecord file sa=00000000 size=ffffffffffffffff

Now send the stub SREC data down to the board using the terminal emulator’s ‘send ASCII’ (or similar) functionality.

Red Hat has experienced some sensitivity to how fast the data is written to the board. Under Windows you should configure Minicom to use a line delay of 100 milliseconds. Under Linux, use the slow_cat.tcl script:

% cd BASE_DIR/packages/hal/mips/ref4955/<version>/misc
% slow_cat.tcl < [path]/gdb_module.srec > /dev/ttyS0

Power off the board, and change it to boot the GDB stubs in big-endian mode by setting the switches like this:

SW1: 00000000 (all levers down) SW2: 10001010

The GDB stubs allow communication with GDB using the serial port at connector PJ7A (lower connector). 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 straight through serial cable.