Two unknown cartridges
Moderator: Moderators
Two unknown cartridges
Hi guys,
I have a couple of cartridges that don't appear to work when I plug them in. Is there any tricks to trying them? One is definitely a UMI and the other with the switch I tried by flipping the switch (while it was off, of course) I have an eprom programmer. Can I read these these eproms? I also tried cleaning the contacts and plugging them in a few times just in case.
Any ideas on what they may be or how I can access them (if it's possible) is much appreciated.
I have a couple of cartridges that don't appear to work when I plug them in. Is there any tricks to trying them? One is definitely a UMI and the other with the switch I tried by flipping the switch (while it was off, of course) I have an eprom programmer. Can I read these these eproms? I also tried cleaning the contacts and plugging them in a few times just in case.
Any ideas on what they may be or how I can access them (if it's possible) is much appreciated.
- Attachments
-
- Unknown cartridge
- Unknown.jpg (57.88 KiB) Viewed 3658 times
-
- UMI cartridge
- UMI cart.jpg (62.46 KiB) Viewed 3658 times
- eslapion
- ultimate expander
- Posts: 5458
- Joined: Fri Jun 23, 2006 7:50 pm
- Location: Canada
- Occupation: 8bit addict
Re: Two unknown cartridges
The upper photo is obviously of a VIC-1110 8k expansion which was customized by the addition of a ROM chip and switch to toggel it.
The lower board also hard 4 chips of 2k x 8 SRAM so I suspect it too is an 8k expansion but there is a fifth chip on the top and I wouldn't know what that is.
The lower board also hard 4 chips of 2k x 8 SRAM so I suspect it too is an 8k expansion but there is a fifth chip on the top and I wouldn't know what that is.
Be normal.
Re: Two unknown cartridges
Thanks for the reply eslapion.
I did look up the chips and they are mostly all RAM except for the chips you mentioned. The top board has a 2532 EPROM that I have read and placed a copy here: http://vintagecomputer.ca/download/comm ... 0-2532.zip I don't know how one would figure out what the code is but if someone is interested in taking a look, I would appreciate it.
In either case, I don't see any difference when I plug these in. Both have dip switches but the VIC-1110 cartridge has more switches than what I've been able to find in documentation. The previous owner was a programmer so it might be interesting what is there.
Thanks again.
I did look up the chips and they are mostly all RAM except for the chips you mentioned. The top board has a 2532 EPROM that I have read and placed a copy here: http://vintagecomputer.ca/download/comm ... 0-2532.zip I don't know how one would figure out what the code is but if someone is interested in taking a look, I would appreciate it.
In either case, I don't see any difference when I plug these in. Both have dip switches but the VIC-1110 cartridge has more switches than what I've been able to find in documentation. The previous owner was a programmer so it might be interesting what is there.
Thanks again.
Re: Two unknown cartridges
Eslapion,
I saw your upgrade hack in the Wiki so I took a couple of pictures of the VIC-1110 if you'd like to see how this hack was done. It may be common but I couldn't find this anywhere.
I saw your upgrade hack in the Wiki so I took a couple of pictures of the VIC-1110 if you'd like to see how this hack was done. It may be common but I couldn't find this anywhere.
- Attachments
-
- VIC-1110 hack front
- VIC-1110 Front.jpg (65.48 KiB) Viewed 3637 times
-
- VIC-1110 hack back
- VIC-1110 Back.jpg (89.5 KiB) Viewed 3637 times
Re: Two unknown cartridges
I extracted the code with a hex editor and then ran it thru a disassembler at:
http://www.e-tradition.net/bytes/6502/disassembler.html
This is what I got from it. The code from the bin file should be mapped at $6000. This is the first few lines:
I tried attaching the file in VICE as a cart and typing 'SYS 24576' to start it to no avail. Maybe it needs to be write protected? Anyone else?
http://www.e-tradition.net/bytes/6502/disassembler.html
This is what I got from it. The code from the bin file should be mapped at $6000. This is the first few lines:
Code: Select all
* = 6000
6000 4C 0C 60 JMP $600C
6003 4C 3F 60 JMP $603F
6006 4C CF FF JMP $FFCF
6009 4C D2 FF JMP $FFD2
600C 78 SEI
600D AD 18 03 LDA $0318
6010 85 0D STA $0D
6012 AD 19 03 LDA $0319
6015 85 0E STA $0E
6017 AD AF 6E LDA $6EAF
601A AE B0 6E LDX $6EB0
601D 8D 16 03 STA $0316
6020 8E 17 03 STX $0317
6023 20 D6 6C JSR $6CD6
6026 A9 00 LDA #$00
6028 85 FD STA $FD
602A 85 FE STA $FE
602C A9 80 LDA #$80
602E 20 90 FF JSR $FF90
6031 A9 FF LDA #$FF
6033 85 16 STA $16
6035 A9 00 LDA #$00
6037 85 0F STA $0F
6039 85 0C STA $0C
603B 85 2F STA $2F
603D 58 CLI
603E 00 BRK
603F 20 B6 6C JSR $6CB6
6042 68 PLA
6043 85 05 STA $05
6045 68 PLA
6046 85 04 STA $04
6048 68 PLA
6049 85 03 STA $03
604B 68 PLA
604C 85 02 STA $02
604E 68 PLA
604F 85 01 STA $01
6051 68 PLA
6052 85 00 STA $00
6054 BA TSX
6055 86 06 STX $06
6057 38 SEC
6058 A5 01 LDA $01
605A E9 02 SBC #$02
605C 85 01 STA $01
605E A5 00 LDA $00
6060 E9 00 SBC #$00
6062 85 00 STA $00
6064 20 D6 6C JSR $6CD6
Rob
Re: Two unknown cartridges
The fifth chip might be a multichannel relay switch. If so, the dip switch may enable the user to choose the amount of memory that is added.eslapion wrote:The upper photo is obviously of a VIC-1110 8k expansion which was customized by the addition of a ROM chip and switch to toggel it.
The lower board also hard 4 chips of 2k x 8 SRAM so I suspect it too is an 8k expansion but there is a fifth chip on the top and I wouldn't know what that is.
- eslapion
- ultimate expander
- Posts: 5458
- Joined: Fri Jun 23, 2006 7:50 pm
- Location: Canada
- Occupation: 8bit addict
Re: Two unknown cartridges
The DIP switches are connected to the !CS lines for BLK 1,2,3,5Kakemoms wrote:The fifth chip might be a multichannel relay switch. If so, the dip switch may enable the user to choose the amount of memory that is added.
The TI chip is a form of address decoder. Why they would use such a large chip instead of a simple 74LS138, I don't know.
Ergo, what you see is a 8k expansion made up of four 2k x 8 SRAM chips with DIPs to select where to make it appear to the VIC.
These Mitsubishi chips are the same ones used in most Commodore VIC-1110 and VIC-1111
Be normal.
Re: Two unknown cartridges
Ah you are absolutely right. I confused the 24-pin 7240A as a newer 7240SEL.
In that respect one can put the memory at BLK 1 by setting switch 4, BLK 2 by setting switch 3.. and so on.
A picture of the backside would be interesting.
In that respect one can put the memory at BLK 1 by setting switch 4, BLK 2 by setting switch 3.. and so on.
A picture of the backside would be interesting.
Re: Two unknown cartridges
No problem. I still haven't been able to figure these out but here's a pic in any case:Kakemoms wrote:A picture of the backside would be interesting.
Re: Two unknown cartridges
Ok. Well, the only thing I can see is that three address pins are connected to the TI 7240A, e.g. CA13, CA12 and CA11.
So its apparent that there is some simple logic in the 7240A which decides which memory chip that will respond to the memory access from the Vic-20.
E.g. $1FFF are 13 bits (8K byte), $FFF are 12 bits (4K byte) and $7FF are 11 bits (2K byte). So if each chip was 2K byte, you would need CA12 and CA13 to determine which chip to access (00,01,10,11). Since CA11 is connected it may indicate that the board was made to also function with 1K byte chips (for a total of 4K byte expansion).
Maybe eslapion has a better explanation.
As for how to fix it, it might be a cracked solder joint or fried chips. If you can find "new" memory chips you could try to swap them. Use a ohm-meter to check joints. I doubt you can find a replacement for the TI 7240A.
I also noted from the front side picture that all the dip switches are set to the same position (its hard to see if they are on or off). That might confuse the Vic-20, so try setting the BLK1 to ON and the others to OFF. Please note that if you put the memory to BLK5 it will not be available to BASIC.
So its apparent that there is some simple logic in the 7240A which decides which memory chip that will respond to the memory access from the Vic-20.
E.g. $1FFF are 13 bits (8K byte), $FFF are 12 bits (4K byte) and $7FF are 11 bits (2K byte). So if each chip was 2K byte, you would need CA12 and CA13 to determine which chip to access (00,01,10,11). Since CA11 is connected it may indicate that the board was made to also function with 1K byte chips (for a total of 4K byte expansion).
Maybe eslapion has a better explanation.
As for how to fix it, it might be a cracked solder joint or fried chips. If you can find "new" memory chips you could try to swap them. Use a ohm-meter to check joints. I doubt you can find a replacement for the TI 7240A.
I also noted from the front side picture that all the dip switches are set to the same position (its hard to see if they are on or off). That might confuse the Vic-20, so try setting the BLK1 to ON and the others to OFF. Please note that if you put the memory to BLK5 it will not be available to BASIC.
Re: Two unknown cartridges
You can get an replacement of the SN44361-8Q here:
http://www.ecrater.com/p/8506623/lot-of ... sn44361-8q
It is designated 7906 instead of 7240 so it may or may not work as a replacement.
There are alot of old TI databooks here:
http://bitsavers.trailing-edge.com/pdf/ti/_dataBooks/
Maybe you can find something there.
http://www.ecrater.com/p/8506623/lot-of ... sn44361-8q
It is designated 7906 instead of 7240 so it may or may not work as a replacement.
There are alot of old TI databooks here:
http://bitsavers.trailing-edge.com/pdf/ti/_dataBooks/
Maybe you can find something there.