[ECOS] GDBstub porting for vrc4375

["Ling Su" <lingsu@palmmicro.com>]

Dear All,

As you may know, I am porting GDB stub for NEC DDB-VRC4375 based on VRC4373
source code. I got following questions, anybody can help me?

<1>. After try to burn code into EPROM and test it on board for lots of
times, I began to use PMON to debug my GDB stub in RAM startup. I disabled
MMU, Cache. But I found there are some conflicts when the GDB stub and PMON
try to access serial port together, so the program usually dead in trying to
write char to serial port. I am not sure if there is any method I can slove
this? I hope I can use another serial port to connect with GDB in this
debugging session, is that possible? there are two ports on the board. But I
am not sure to avoid the PMON and the monitor to access the serial port
simutenously.

<2>. There are a 7-segment display on board, according to the document the
address is 0x7c000000, I am trying to write to the address after system
initialization, but it doesn't work. Anything wrong?

Thanks!

-Ling