Amazing PET haul! Help identifying some oddballs.

[Oneironaut]

Greets 6502 Freaks, it's been a while!

I have been picking away on my Vulcan-74 project here and there, but the farm and my 2 day jobs has taken all of my time this summer so far. Winter is always the best time to hide in my lab and have fun, and I am looking forward to posting the progress on my project then.

So, I am out in the Northern Ontario wilderness installing a computerized time lapse system on a 250 foot tower, and after the job I start up a chat with someone there. Well, wadda know, they actually knew of my Vulcan-74 project from postings here and we talked for some time. At the end of the conversation, I was asked...

"Hey, I have a bunch of old Commodore computers in a basement at my camp down the road, you want 'em"?

Well, I followed the usual protocol when asked such a thing, which is...
Say yes, shut up, then open the car doors to load up!

I was amazed to see there were 5 PETs in the collection I was loading, and some of them looked different than the one I already had. Four of them were in nice shape and actually turned on, displaying the usual basic prompt! Here they are...



The 4016 is in amazing shape, all keys working, no monitor burn at all, even the main board is clean.
The interesting one is the one labelled SuperPET SP-9000. Have not seen one of those before!
Even the keyboard is different, more like a C64 or VIC than a PET.

Inside the SuperPET is an addon board that has extra RAM and some various built in Apps.
There is even a switch on the side to change the BOOT ROM and run different Apps...



Notice the differences in the keyboard from the standard 4016 and the SuperPET...



The other PETS seem mote common, 4016, 4032, and a pair of 2001 series.

So I am curious as to how rare the SuperPET may be?
I found a few photos of it online, but ir appears to have been a limited production system.

When I have more time, I will do a full restore with tons of photos on my Blog...
https://www.atomiczombie.com/blogs/

Cheers,
Radical Brad

[BigEd]

Congrats! That's a photo of pi pets, I take it.

SuperPET is a great find, although I couldn't say how rare it might be.

[Oneironaut]

Thanks!
Amazing how robust these are. Powered on after 40 years and ready to rumble!

The 4016 even has sound. A small piezo speaker on the main-board offers a startup ring.
Never knew they released one with sound.

Brad

[Dr Jefyll]

Congrats! -- what a lucky find! (Having said that, I don't really wish to encounter such luck myself. I have enough lucky finds in storage already! )

Oneironaut wrote:

Inside the SuperPET is an addon board that has extra RAM and some various built in Apps.
There is even a switch on the side to change the BOOT ROM and run different Apps...

More than a little intriguing. I wonder what the add-on board could be... and, do they really mean 6809 ?!!

-- Jeff

[drogon]

Dr Jefyll wrote:

Congrats! -- what a lucky find! (Having said that, I hope I don't encounter such luck myself. I have enough lucky finds in storage already! )

Oneironaut wrote:

Inside the SuperPET is an addon board that has extra RAM and some various built in Apps.
There is even a switch on the side to change the BOOT ROM and run different Apps...

More than a little intriguing. I wonder what the add-on board could be... and, do they really mean 6809 ?!!

-- Jeff

Yes.

https://en.wikipedia.org/wiki/Commodore ... 000_series

-Gordon

[BitWise]

The superpet was fun. We had one at my college along with all the Waterloo University languages.

You need to find the disks and manuals to go with it. I have a copy of the assembler manual somewhere. It was the assembler than inspired me to develop a 6502 assembler with structured assembly features.

[Oneironaut]

Greets Doc!
Interesting, I never even read the switch labels!
Back soon, going to lift the cover and have a look.

Dr Jefyll wrote:

Congrats! -- what a lucky find! (Having said that, I don't really wish to encounter such luck myself. I have enough lucky finds in storage already! )

Oneironaut wrote:

Inside the SuperPET is an addon board that has extra RAM and some various built in Apps.
There is even a switch on the side to change the BOOT ROM and run different Apps...

More than a little intriguing. I wonder what the add-on board could be... and, do they really mean 6809 ?!!

-- Jeff

[Oneironaut]

Thanks for all the info!
Indeed there is a 6809 in there...



Brad

[BigEd]

Yes, the SuperPET - dare I say it - turns the PET into a seriously capable computer.

Here's a previous thread:
Super Pet (Commodore) How The SuperPet Came to be
(to which I've just added some notes, and a link back here)

[GARTHWILSON]

This might be a good time to draw attention to André Fachat's very impressive pages on this site, some specifically involving PETs:
http://6502.org/users/andre/

[Oneironaut]

Nice site! I remember landing there when I was restoring my first PET.

I do have 2 questions that I have not found answers for, so perhaps someone here might know. Both have to do with the PET monitor...

1) On the video input pin (PIN.1), I know the PET drives this from a 5v shift register, so it is a digital signal. But, will the drive circuitry accept an analog signal? If so, this would allow greyscale images. I assume it would.

2) What is are the horizontal and vertical refresh timings for a PET, and what are the maximum specs for the monitor?

I am sure I will find this info with enough digging when I have time, but if anyone knows these answers, it would be nice to add them here in case someone is searching one day as well.

Ps...
Yes, I ask because I am working on a PET expansion project based loosely on my Vulcan-74 Video Generator. How can I resist now that I have 6 of them here?

Cheers!
Brad

GARTHWILSON wrote:

This might be a good time to draw attention to André Fachat's very impressive pages on this site, some specifically involving PETs:
http://6502.org/users/andre/

[Oneironaut]

A little dig around André Fachat's site answered the timing part of my question....

4032 4032 8032 8032 CS/A65 CS/A65
text graph text graph 1 MHz 2 MHz
----------------------------------------------------------------------------------------------------------
CCLK rate [MHz] 1 1 1 1 1 2

R0 (hor. total) 49 49 63 63 63 126
R1 (hor. displ) 40 40 40 40 40 80
R2 (hor. sync) 41 41 50 50 50 100
R3 (syn width) 15 15 8 8 3 6

R4 (vert. total) 39 49 32 36 41 41
R5 (vert. adjust) 0 0 16 17 0 0
R6 (vert. displ) 25 25 25 25 25 25
R7 (vert. sync) 32 37 29 32 33 33

R9 (scanlines/char-1) 9 7 8 7 7 7

time per scanline [us] 50 50 64 64 64 63.5
scanl./char
(R9+1) 10 8 9 8 8 8
time per charline [us]
(R9+1)*t/scanline 500 400 576 512 512 508
scanlines total
(R9+1)*(R4+1)+R5 400 400 313 313 336 336
time/fram [ms]
scanl tot. * t/scanl 20.0 20.0 20.0 20.0 21.5 21.3
framerate [Hz]
fram/time 50 50 50 50 47 47



Sorry for the messed table. Tabb are different in this forum.
In case anyone else lands here due to a google search, here is the original source....

http://6502.org/users/andre/petindex/crtc.html

And a great table with most timing values and specs listed....

inchocks.co.uk/commodore/PET/PET_CRTC.xls

As for the analog nature of the video input signal, I will test this myself over the weekend if I get rained out of my outdoor work.
Will post my results here, with photos.

Brad

[BillO]

Oneironaut wrote:

A little dig around André Fachat's site answered the timing part of my question....

Code: Select all

                      4032    4032    8032    8032    CS/A65   CS/A65
                      text    graph   text    graph   1 MHz    2 MHz
----------------------------------------------------------------------------------------------------------
CCLK rate [MHz]        1       1       1       1       1        2

R0 (hor. total)        49      49      63      63      63       126
R1 (hor. displ)        40      40      40      40      40       80
R2 (hor. sync)         41      41      50      50      50       100
R3 (syn width)         15      15      8       8       3        6

R4 (vert. total)       39      49      32      36      41       41
R5 (vert. adjust)      0       0       16      17      0        0
R6 (vert. displ)       25      25      25      25      25       25
R7 (vert. sync)        32      37      29      32      33       33

R9 (scanlines/char-1)  9       7       8       7       7        7

time per scanline [us] 50      50      64      64      64       63.5
scanl./char
 (R9+1)                10      8       9       8       8        8
time per charline [us]
 (R9+1)*t/scanline     500     400     576     512     512      508
scanlines total
 (R9+1)*(R4+1)+R5      400     400     313     313     336      336
time/fram [ms]
 scanl tot. * t/scanl  20.0    20.0    20.0    20.0    21.5     21.3
framerate [Hz]
 fram/time             50      50      50      50      47       47

Sorry for the messed table. Tabb are different in this forum.
In case anyone else lands here due to a google search, here is the original source....

http://6502.org/users/andre/petindex/crtc.html

And a great table with most timing values and specs listed....

inchocks.co.uk/commodore/PET/PET_CRTC.xls

As for the analog nature of the video input signal, I will test this myself over the weekend if I get rained out of my outdoor work.
Will post my results here, with photos.

Brad

Use the Code tags to create better tables.

[Oneironaut]

I had an hour tonight in the Commodore Cave, and managed to verify that the Video Input to the PET Monitor is indeed digital only.



I churned out some simple AVR assembly to generate a valid video frame for the PET Monitor, using the following timing...

// HORIZONTAL SYNC : 20 KHZ NEG
// VERTICAL SYNC : 60 HZ NEG
// PIXEL CLOCK = 20 MHZ
// TOTAL LINE = 1000 CLK
// ACTIVE LINE = 720 CLK
// HSYNC TIME = 290 CLK
// VSYNC TIME = 40 LINES

The monitor locked right on to the signal, so I guess the data in the Excel sheet was bang on!



I soon realized that the raster would only draw if the voltage was above 2.5 volts, so it is completely digital.
In the photo above, I am feeding a 5MHz signal to the Video Input, which is why it generates vertical bars.

Not all is lost though, I am now looking at the schematic and should be able to tap the Video Input past the integrator, allowing me to feed an analog voltage in there to generate shades of green.

No Commodore ever gets mods in my cave, so I will only solder a wire to the board and not remove anything. I think this will work.

The end goal is a fun add on card that just fits between the monitor connector on the main board and CRT to allow the PET to draw up some 720x400 8 bit graphics! That's 256 shades of green at a resolution of 720x400, so it will be quite impressive considering a stock PET.

The graphics will be delivered by a simplified version of my Vulcan-74 Video Engine, just made of some SRAM and basic logic parts. All of the original PET Video generated by the 6545 Video IC will also be displayed, so 100% compatibility will also be maintained. The new Video will just be a combination of the original and the enhanced.

As for the point of entry, I have targeted two possible places on the Monitor board as shown...



Not sure if my Monitor board is the same, but I assume the electronics will be similar. Another possibility is just to have the add-on board drive full green digital during the active frame, and have the "luma" delivered to the point on the board that controls brightness. This would also work.

Should be a fun and simple project for rainy summer days since I won't have any real hackin' time until winter again.

Why????
Cuz I can!

Cheers,
Radical Brad.

[Oneironaut]

Just did one more test before my morning day routine, and.... success!
Tapping this point here allowed my to feed the output of an 8 bit R2R DAC to the monitor and get 256 shades of grey (green)...



Now I can drive the video gun directly without the integrator converting it into a digital signal.
It's not really a "mod" as I consider it, so not against my rules of not modifying any Commodore equipment in my cave!
Just needed to solder a wire at that point, which is easily visible by looking at the Monitor ma inboard when the lid is open.

I will start a new thread later, now that I know my evil plan to give the PET 256 shades of 720x240 video shall work.
This is going to be the first example of a PET displaying analog video ever.
All of the GFX boards I researched only upped the resolution, but never put out shades, which is where the real ability to display GFX is at.

Cheers,
Radical Brad