[channelf] Videocart dumper experiments continue...

  • From: Fredric QJ Blåholtz <e5frog@xxxxxxxxx>
  • To: channelf@xxxxxxxxxxxxx
  • Date: Tue, 18 Aug 2009 12:21:09 +0200

I made a lot of dumps yesterday, about a third of the working PCB:s
left over from making Pac-Man cartridges was holding in the code of
the first or second PSU - only one of them released the data to the
databus...

When starting at my personal collection of carts I've had half dumps
of two carts of twelve so far - don't know why they do that, I imagine
it's the PC0 reset signals that aren't proper. Of all dumps made in
total (maybe 30-40) with all versions that I havew tested there has
been two that has dumped all code but left a gap between the first and
second PSU - very easy to fix but that too seems to have something to
do with resetting the PC0.

I have marked all the "hard" ones and I'll see if they dump OK when I
get the 20MHz PIC16F628A - otherwise I'll try and find a signal scheme
that works. As I might have mentioned before there's a gap too large
(according to the datasheets of the 3851 PSU and 3853 SMI) between the
first write-pulse and the correct ROMC-signal of the PC0-reset so I'll
probably try to adjust that first and then maybe I'll try and get it
(PHI) closer to 2MHz so I can try and follow the exact times in the
datasheets.

Any suggestions are welcome - why not build one of your own and we can
compare results?

/ Fredric

-- 
__________________________________
* Fairchild Channel F collector extraordinaire *
http://go.to/channelf - The Gallery of Channel F

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  • » [channelf] Videocart dumper experiments continue... - Fredric QJ Blåholtz