[N8VEM: 17476] SBC V2 troubleshooting

[neilbradley]

I managed to hook up my SBC V2's serial port to an adapter and get serial
output. I get:

RomWBW..

... then nothing. Each time I hit reset, I get this same text message out
the UART. I've tried combinations of all other settings of jumpers, and it
either results in identical behavior, or nothing at all on the output of
the serial port.

I am using a 29F040 and built it as such with WBW with "std". This is the
standalone SBC V2. I haven't yet plugged it in to the backplane.

I don't have the Dallas 1302 installed (haven't found it). Could this be
the problem? Any help on what I can do to troubleshoot this would be
greatly appreciated.

-->Neil

[oscarv]

Neil,

If you only see two dots after RomWBW, it means that boot code in phase 1,
prior to relocating to upper memory, is working but the jump to the
relocated boot code is not working. See source file bootapp.asm, and search
for "CALL

Post by neilbradley
I managed to hook up my SBC V2's serial port to an adapter and get serial
RomWBW..
... then nothing. Each time I hit reset, I get this same text message out
the UART. I've tried combinations of all other settings of jumpers, and it
either results in identical behavior, or nothing at all on the output of
the serial port.
I am using a 29F040 and built it as such with WBW with "std". This is the
standalone SBC V2. I haven't yet plugged it in to the backplane.
I don't have the Dallas 1302 installed (haven't found it). Could this be
the problem? Any help on what I can do to troubleshoot this would be
greatly appreciated.
-->Neil

[oscarv]

Neil,

Pls ignore the previous message - I inadvertently sent it incomplete... and
it seems Google Groups does not allow editing of messages.

What I meant to say...

If you only see two dots after RomWBW, it means that boot code in phase 1,
prior to relocating to upper memory, is working. So the serial port
obviously got initialised, and the boot code was copied from low to high
memory. That's when the second dot is printed.

But the jump to the relocated boot code is not working. Because straight
after that jump, a 3rd dot is printed.

See source file bootapp.asm, and search for "CALL XIO_DOT".

I fail to see why the absence of the 1302 could cause this problem. There
is nothing relating to the 1302 in the source code between the printing of
dots 2 and 3... But it sounds like a DS1210 problem: no battery inserted
and the DS1210 installed? Have a look at this conversation from a few
months ago: (link<https://groups.google.com/forum/#!searchin/n8vem/zeta$20battery$20/n8vem/t52Hhe92m9U/_vWqxphs4bYJ>).
It makes your RAM disfunctional in a devilishly misleading way.

If this is not the problem, it must be something in the memory bank
management or a fautly RAM?


Regards,

Oscar.

[neilbradley]

Oscar, thanks so much for the pointer! I don't have a battery connected to
it, and that may be the issue. I was handling the board while hitting
reset, and I did find a situation where it spit out "N8VEM xxxxxx" and then
hung, and in retrospect, I may have been touching the battery header. Odd
that it's that sensitive. ;-/

Anyway, I'll give that a shot - thanks again for the help!

[Andrew Bingham]

I had the same issue when I built my Zeta. Tried it with no battery, no
go. The RAM is write-protected unless you have a battery in, so the first
few instructions in the ROM run and then it fails as soon as it tries to
read something that was written to RAM.

Oscar, thanks so much for the pointer! I don't have a battery connected to

it, and that may be the issue. I was handling the board while hitting
reset, and I did find a situation where it spit out "N8VEM xxxxxx" and then
hung, and in retrospect, I may have been touching the battery header. Odd
that it's that sensitive. ;-/

Anyway, I'll give that a shot - thanks again for the help!