SH3/CQ7708 Hardware Setup

Preparing the board

Make sure the DIP switches on the board are set as follows:

SW1-1 ON
SW1-2 OFF   
SW1-3 ON   
SW2-1 ON   
SW2-2 ON   
SW2-3 OFF   

If you are using a straight through serial cable which has flow control lines, you will also need to cut JP12 (5-6) as the flow control lines can cause NMIs.

eCos GDB Stubs

The eCos installation CD contains a copy of the eCos GDB stubs in binary format which must be programmed into an EPROM or FLASH and installed on the board.

Programming the stubs in EPROM/FLASH

The board can use different sizes of ROMs. Use this table to adjust the board’s jumpers to the ROM sizes you are using.

size(kbit)    JP7   JP9   JP10   JP11     
256           2-3   2-3   open   open     
512           1-2   2-3   open   open     
1000          1-2   open  open   2-3     
2000          1-2   1-2   open   2-3     
4000          1-2   1-2   short  2-3     
8000          1-2   1-2   short  1-2

There are two ways to program the stubs. We advise you to use method 1, since it is simpler. Method 2 is unsupported and requires a bit of fiddling.

Method 1:

Program the binary stub image into two EPROMs, E and O. EPROM E should contain the even bytes, and O the odd bytes (your EPROM programmer should have the ability to split the image).

EPROM E should be installed in socket IC8, and EPROM O should be installed in socket IC4.

Set JP6 to 16 bit mode (1-2 soldered, 2-3 cut) Set SW1-4 to ON and SW2-1 to OFF.


Assuming that the stub binary is smaller than 32 KB, you can install it in a single EPROM.

Compile the mkcqrom.c program found in the misc directory.

Use it to convert the binary image to the required format. See the mkcqrom.c source for a description of what is done, and why it is necessary.

 % mkcqrom gdb_module.bin gdb_mangled.bin

Program the gdb_mangled.bin file into an EPROM and install it in socket IC4

Set JP6 to 8 bit mode (cut 1-2, solder 2-3)

The GDB stubs allow communication with GDB using the serial port at connector CN7. 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.