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Pet Vet & Pet Disk Issues

Nicolas

Member
Joined
Jul 9, 2013
Messages
26
Location
Nicosia - CYPRUS
Hi everybody, I got a Pet Disk and a Pet Vet few months back for my 8032 PET. The Pet Disk works just fine, I am able to read and write files, including those that already were present on the 2GB micro SD card that came with the Pet Disk.

Does anybody know where I could get hold of Commodore Pet arcade games, or other BASIC games for the 80 column PET. Most I have been able to find on-line are for the 40 column Pet.

Another issue that is bothering me is the fact that once I install the Per Vet in the 6502 socket, my display starts to become a little bit shakey, and not rock steady like it is without the Pet Vet board installed. In all other respects, my 8032 seems to work fine with the Pet Vet.

I thought, though, that this Pet Vet board by-passes the RAM, SRAM and ROM chips and uses its own on board BASIC 4, memory e.t.c. If however, I try to reomove any of the motherboard's 2114s, or 4116, or ROM chips, the machine does not boot, unless fully polupated with its original chipload.

Is that how things should be or I'm I doing something wrong? The switches on the PET VET are as they should be for an 80 column BASIC 4 machine. As I mentioned the computer works fine with the PET VET, apart from the shaky display, especially in the bottom half of the screen, as if it is a little bit out of sync....

Could somebody enlighten me please?

Thanks a lot in advance.
 
Hi nicolas

here are some pet games :

http://awesome.commodore.me/pet/pet-games/
http://www.video-games-museum.com/en/sys/67/3

regarding the petvet :

I use also the petvet and have the same shakey display when petvet is installed i have notice that when the pet is open the monitor stops to be shakey.
As i use the petvet for diagnostics it did not worry me. I also notice some incompatibilitys with some non original 6502 processors.

the petvet should work in the PET as a complete RAM/ROM replacement (except for video RAM).
For exemple If you changed the jumper marked as 'switch 1' to ON, the PETvet will be in bypass mode and will not make use of the RAM chip on the PETvet.

see: http://www.bitfixer.com/bf/petvet/petvet-operation

Kind regards, techtatan
 
Interesting.

I have a PetVet Mike sent me to try but I've never had any luck with it on both my PET 3032 boards. I can't remember the details now but behaviour was erratic. Despite scratching our heads over the symptoms Mike (the creator) and I never did get to the bottom of it. Either the PetVet itself had a fault or there was something about my boards that were just "different".

PetDisk works just fine!

Tez
 
I bought a PetVet for my 2001N, because I thought I would need it. Whilst waiting for it to arrive, I fixed my PET, so I don't need it. I did plug it in, to play around with C= BASIC 2. That doesn't work. The only thing that works is BASIC 4. With BASIC 4, it seems to do everything I'd expect it to do. I don't get any shaky video, or any other symptoms.
 
Shaky video was never a symptom with my malfunctioning PetVet. The screen was rock solid.

I've just dug through the archives. Here were the symptoms (quoting a summary from an email by Mike):

"- with basic4 roms on the mainboard, on setting 4 there are still some

issues with running loaded programs, but entered code is ok
- with basic2 roms on the mainboard, on setting 4 things were ok

using ROM images from the PETvet,
- basic2 setting had corrupted strings and issues loading
- basic4 loads but usually won't run"

Looking at old emails, Mike did mention he was going to tweak some things with later runs of PetVet. Whether this was done or not I'm not sure. These issues therefore may relate to earlier versions of the device.

Tez
 
Another issue that is bothering me is the fact that once I install the Per Vet in the 6502 socket, my display starts to become a little bit shakey, and not rock steady like it is without the Pet Vet board installed. In all other respects, my 8032 seems to work fine with the Pet Vet.

The PETVet comes preloaded with ROM files for a 60 Hz system on BASIC 4. Did you specify a 50 Hz rom set? If not, you may have to upload a revised file into your PETVet. Provisions are made for this.

I thought, though, that this Pet Vet board by-passes the RAM, SRAM and ROM chips and uses its own on board BASIC 4, memory e.t.c. If however, I try to reomove any of the motherboard's 2114s, or 4116, or ROM chips, the machine does not boot, unless fully polupated with its original shipload.

You must use the 2114 video RAMs! PETVet does not replace those. It does not care about the 4116s or ROMs. You should be able to leave those in or out. A 74LS245 transceiver isolates the data bus from the PET when the PETVet is using its own memory.
 
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For exemple If you changed the jumper marked as 'switch 1' to ON, the PETvet will be in bypass mode and will not make use of the RAM chip on the PETvet.
techtatan,

I did not know that. I assume it bypasses both RAM and ROM? Did Mike mention this to you?
-Dave
 
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I bought a PetVet for my 2001N, because I thought I would need it. Whilst waiting for it to arrive, I fixed my PET, so I don't need it. I did plug it in, to play around with C= BASIC 2. That doesn't work. The only thing that works is BASIC 4. With BASIC 4, it seems to do everything I'd expect it to do. I don't get any shaky video, or any other symptoms.

If you have a newer Commodore main board that uses a 6545 CRT Controller, then only BASIC 4 will work as it properly initializes the CRTC.
 
Shaky video was never a symptom with my malfunctioning PetVet. The screen was rock solid.

I've just dug through the archives. Here were the symptoms (quoting a summary from an email by Mike):

"- with basic4 roms on the mainboard, on setting 4 there are still some

issues with running loaded programs, but entered code is ok
- with basic2 roms on the mainboard, on setting 4 things were ok

using ROM images from the PETvet,
- basic2 setting had corrupted strings and issues loading
- basic4 loads but usually won't run"


Hi Tez! Long time no chat.

With these symptoms I would suspect a flaky 74LS245 on the PETVet. If it is on a socket, I would replace it and try it again.

If that doesn't fix it, you could sent it to me and I would reload the firmware into the ATMEGA chip in case it got corrupted. You probably have the prototype firmware that does not include the boot program to allow reprogramming the FLASH memory without the need for an AVR programmer. I have reprogrammed the microcontroller chip in my PETVet using something called the AVRISP mkII In-System Programmer from Atmel and it works fine. Using this device, the ATMEGA chip does not have to be removed from the PETVet module.

Best regards,
Dave
 
hi dave

yes mike did mention that in a mail when i have issue with a non compatible processor to petvet. I have read the mails again and find out that i asked him if there was a ROM bypass but unfortunatly he never answered the quetion, maybe the question was too drowned in the discussion ?

Kind regards, techtatan
 
Hi Tez! Long time no chat.

With these symptoms I would suspect a flaky 74LS245 on the PETVet. If it is on a socket, I would replace it and try it again.

If that doesn't fix it, you could sent it to me and I would reload the firmware into the ATMEGA chip in case it got corrupted. You probably have the prototype firmware that does not include the boot program to allow reprogramming the FLASH memory without the need for an AVR programmer. I have reprogrammed the microcontroller chip in my PETVet using something called the AVRISP mkII In-System Programmer from Atmel and it works fine. Using this device, the ATMEGA chip does not have to be removed from the PETVet module.

Best regards,
Dave

Hello Dave,

Long time, no chat indeed. I haven't been pampering my PET for some time.

Thanks for that tip. Given the problem was manifest with both PET boards I have it would be logical if it was something with the PetVet. I'm not sure if it has the boot program or not.

Anyway, when I get some time I'll drag the PET out, do what you suggest and see if that solves the problem.

Thanks

Tez
 
hi dave

yes mike did mention that in a mail when i have issue with a non compatible processor to petvet. I have read the mails again and find out that i asked him if there was a ROM bypass but unfortunatly he never answered the quetion, maybe the question was too drowned in the discussion ?

Kind regards, techtatan

Techtatan,
I would guess that if switch #1 is 'ON' that all of PETVet is bypassed. One could just leave the PETVet in place but using the normal PET devices until something breaks. Then a flip of the switch and you are immediately back on the air using the PETVet memory. That is a handy feature.

Is your PET a 50 Hz system?
-Dave
 
Does anybody know where I could get hold of Commodore Pet arcade games, or other BASIC games for the 80 column PET. Most I have been able to find on-line are for the 40 column Pet.

There're not too many native 80 columns games; but you can use 80 to 40 columns converters like "cbm4032 any hz.prg". Loading this tool before the game you'll be able to see fine most of the 40 columns software.
You can find it in the zimmers archive: ftp://ftp.zimmers.net/pub/cbm/pet/ALLFILES.html]
 
hi Dave

I would guess that if switch #1 is 'ON' that all of PETVet is bypassed. One could just leave the PETVet in place but using the normal PET devices until something breaks. Then a flip of the switch and you are immediately back on the air using the PETVet memory. That is a handy feature.

You are probably right ! i will ask mike about it again. As in a case of diagnosis I would have preferred to have the possiblility of bypass RAM and ROM separetly !

Is your PET a 50 Hz system?

Once again you must be right regarding the shakey screen ! indeed my PET is a 50hz system. And in bypass mode (i tested it today) the display is perfectly normal ! so this also leeds to more than just RAM bypass on petvet !

But as i got the info directly from mike i relay it like i got it in my original post! I did not remember That he never answered my question about ROM bypass as dicussions goes over multiple mails.

Sorry if i misinformed Nicolas my goal was to help the best i can :)

Kind regards
 
If you have a newer Commodore main board that uses a 6545 CRT Controller, then only BASIC 4 will work as it properly initializes the CRTC.

Hello Dave,

The machine is a 2001-32N, with the original board. Of course, that doesn't mean much, and I forgot what we call the different motherboards. It is not the original 8k 2001 board, and it is not the 'universal' board. It does not have a 6545 CRTC. The board, according to the previous owner, originally came with BASIC 2 ROMs, and it was upgraded to BASIC 4. It does have a sticker inside the case that reads "upgraded to 4.0" but the board is the same one that had the BASIC 2 ROMs, or at least, it's one just like it.

I suspected an error in the BASIC 2 ROM on the PetVet, though I don't know how that would happen. So, maybe there's something else different about my PET.

Thanks
Matt
 
I suspected an error in the BASIC 2 ROM on the PetVet...

Yes, since it is not a board with the 6545, I agree with you, the BASIC 2 data must be corrupted. There is a way to reload the file which includes having an old PC terminal program that still knows about the XMODEM protocol. But if BASIC 4 is solid, there may not be much of a need.
-Dave
 
Thanks to all you friendly, helpful, wonderful people for all the help offered. My PetVet has switch 1 open (off) but still my motherboard refuses to boot with any ROM out of its socket. About the shaky screen being attributed to the 50/60 Hz issue, I have my doubts since only the bottom part of the screen (bottom 4-6 lines) is shaking a bit, the top part being very steady. When I open the Pet cover and the distance between the monitor and the PetVet increases, then things improve but problem is not going away completely. Could be some form of interference requiring some form of shielding, but don't really know.

Important is that my pet is working fine and provides me some quality time with my kids who are more impressed by writing simple BASIC routines than playing with their playstation or iPads.

Many thanks again for all the help to everybody.

Nicolas
 
When I open the Pet cover and the distance between the monitor and the PetVet increases, then things improve but problem is not going away completely. Could be some form of interference requiring some form of shielding, but don't really know.
Nicolas,
Yes, it sounds like RFI noise into the CRT. Is the braided grounding strap connected between the bottom and top case at the back hinge?

The fact that your PETVet requires all the internal ROMs is a puzzle and indicates something is wrong.
-Dave
 
Hi everyone,

Hope I can help out with the PETvet questions. I have been back in another crazy work mode recently, so I haven't been keeping up with some of the PET stuff as much as I'd like.
So, what switch #1 on the PETvet does is set the entire memory space to passthrough mode, so the 6502 should read/write straight through to the PET motherboard and the onboard PETvet ram is not accessed at all. It does this by writing a set of control bytes into the smaller of the two SRAM chips on the PETvet, this in turn controls the '245 and the '541 chips such that the PETvet ram is always disabled and the address/data busses are passing through straight from the motherboard.

If switch #1 is off, then the switch 2 and 3 settings would determine which ROM set it will load into SRAM before the Atmel backs off and lets the 6502 run the system. If you have switch #1 off, and you still see that the internal ROMs need to be there to run the computer - then something may be truly off. Happy to help look into it further, life as you know has its many distractions which rob valuable vintage computing time but definitely want to help sort this out.

Also if we need to change the ROMsets on the PETvet, it can be done as Dave mentioned with a serial port and an XMODEM transfer. Different ROMs can be inserted at any position in memory by use of a rom-building script on the PETvet section of the side.
 
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