4-slot board UniBios 4.0 - Address Error

[adrianomartins]

Hello,
I have a 4-slot board with UniBios 4.0. When starting up, the following error message is displayed;

I have cleaned the contacts of the cartridge and the board thoroughly, but this has not eliminated the error.
Can anyone tell from the error message where the problem might be?
Thanks a lot!

 

[ack]

The code around that location is this

c09a3a: 3038 0108                 move.w  $108.w, D0
c09a3e: 6100 d778                 bsr     $c071b8
c09a42: 4a6d 0b36                 tst.w   ($b36,A5)
c09a46: 671c                      beq     $c09a64
c09a48: 3038 0108                 move.w  $108.w, D0
c09a4c: b06d 0b38                 cmp.w   ($b38,A5), D0
c09a50: 6706                      beq     $c09a58
c09a52: 426d 0b36                 clr.w   ($b36,A5)
c09a56: 600c                      bra     $c09a64
c09a58: 2278 010e                 movea.l $10e.w, A1
c09a5c: 3011                      move.w  (A1), D0
c09a5e: 806d 0b36                 or.w    ($b36,A5), D0
c09a62: 3280                      move.w  D0, (A1)

It looks like there is either a data or address issue accessing the cart(s). Its loading the contents of address $00010e (from the cart header) into the A1 register, then trying to access data that A1 register now points at. However the location the A1 register points at is likely an odd number, which is not valid and results in the address error exception.

I would go into MemView, then scroll so address 000110 is at the top of the screen and take a picture and post it. It should provide a bit more info on where to look.

Thanks
jim

 

[adrianomartins]

Hi jim
Thanks for fast reply and support.
I also added the first addresses because everything looks empty from address 000080 onwards.

 

[ack]

The pictures are pointing to unibios having slot 4 active but its reading all 0xff's from the cart's P rom.

Try testing each slot individually to see if you get the same results in all slots or just slot 4. I would also check for damage caused by a leaky battery.

With it being all 0xff's I would guess some of the 74ls245s between the cpu and the cart aren't getting enabled.

 

[adrianomartins]

Strangely, the cartridge is in slot 1, but I don't know why slot 4 is displayed. I will try the other slots.

I have replaced the battery and cleaned everything. The circuit board around the battery looks good.

Is there a schematic of the 4-slot board available somewhere?

 

[ack]

Strangely, the cartridge is in slot 1, but I don't know why slot 4 is displayed. I will try the other slots.

hrm maybe its a display bug and unibios must not have any slot active.

Try doing this instead
- power on the board
- press player1 B+C+D buttons when unibios logo displays, this should take you to the hardware test screen
- select the first option, which should take you to the cross hatch
- press D to go to memory viewer

once in the memory view you can use the A button to switch slots. If a slot is empty your screen will likely just be all green.

scroll down to the 000110 address again and take a picture.

 

[Razoola]

From the exception error it seems the Bios cannot see the expected carts data as it should. Instead of getting a valid address from 0x10e, its getting 0xFFFFFFFF. As ack says, this is causing the error as its an odd value. Reading a word from memory must always be an even address.

 

[Syn]

From the exception error it seems the Bios cannot see the expected carts data as it should. Instead of getting a valid address from 0x10e, its getting 0xFFFFFFFF. As ack says, this is causing the error as its an odd value. Reading a word from memory must always be an even address.

How are you, man?