Tape Drives for the VIC, 64 and 128 work well on the PET. In fact you can hook up 2 tape drives on the PET (On non-original PETs the second connector is inside the case, on the left edge of the motherboard.) and can be accessed as device #2.
Besides the ones listed there have been several 3rd party drives made to work with the VIC-20 and Commodore 64, as well as standard cassette recorder “adapters” all of which also will work just as well on the PET.
the PET uses the IEEE-488 interface to connect to disk drives. Back when they were new the drives themselves were pretty expensive (hard drives for microcomputers were a rarity then). The lower capacity drives (2031, 2020, 2040, 4040) are “read compatible” with the later Commodore 64 and VIC-20 1540 and 1541 drives and due to minor format variations it is unwise to try to write to a 1541 formatted disk with a PET drive and visa-versa, but for reading files from the other computer, it is a good method. The low density drives were designed initially for a single-density disk. Double density disks are OK to use. The IBM-PC High Density diskettes are not recommended as they would be unreliable on old drive electronics.
The 8050, 8250 and SFD-1001 use a “Quad Density” format (96 TPI) disk. These disks are not easy to find, as a substitute also use Double Density Diskettes, again the HD disks are problematic on the older hardware. Also you can use the 8250/SFD-1001 as if it were an 8050 drive (to read/write 8050 disks) by running a small BASIC program to reconfigure the drive settings. Unfortunately the 8050, 8250, SFD-1001 are all unable to read or write the low-capacity disk format used by the 2040,3040,4040,2031.
Commodore Model IEEE-488 Printers
I know of only one company that produced a modem and IEEE-488 interface, the company is TNW (the Net Works), and I think they also built the Commodore 8010, an acoustic modem for the PET. I have some notes on using the device but have never actually seen one.
Some electronic devices DO have IEEE-488 interfaces built-in to talk to computers, and the communications protocol is the same as on the PETs, you will need to get the data on how to communicate with your device though (like what device number it is, what commands it knows, etc.)
which should be available from the device's manufacturer.IEEE-488 is also used on some Hewlett Packard computers and is referred to as either the HP-GPIB, HPIB or just GPIB (for General Purpose Interface Bus). Even though IEEE-488 is a standard it was not adhered to precisely by Commodore so some 'tweaking' of your programs may be necessary in order to get non-commodore equipment working. (I.E. convert commands to true ASCII)
Like many other microcomputers of the time the PET was not originally designed to produce sound. A few methods of sound generation have been developed but the most popular employs the use of parallel user port pin M which is used to generate a 'square wave' output by setting the 'handshake register' for port B into a free-running mode. Adjustments to the timing of the handshake and the pattern of the 'wave' adjusts its sound and timbre. You can achieve approximately 3 octaves of notes and various noises with this one voice output.
The latest 4000/8000 (large screen PET) motherboards already have a built-in piezo speaker and also have a bell sound accessible with a print: chr$(7)
Sound Interface Diagram (use mono-spaced font to view properly)
Parallel Port:
1 1 1
1 2 3 4 5 6 7 8 9 0 1 2
= = = = = = = = = = = =
### ######################### ######
= = = = = = = = = = = =
A B C D E F H J K L M N Ground +=====+
! +-----------!AUDIO!
CB2 ! 50-500K res.! AMP !
+-/\/\/\-------+=====+
You can get most of the parts (except the parallel port connector) at Radio Shack, including a low-cost mini amplifier. See below for a source for 12/25 edge board connectors.
The PET was not initially designed for joysticks but a determined user had devised a dual-joystick interface employing the parallel port. This interface allows you to plug in standard Atari/Commodore compatible joysticks….
Interface Diagram (use mono-spaced font to view properly)
Looking at back of user port 1 1 1
1 2 3 4 5 6 7 8 9 0 1 2
= = = = = = = = = = = =
### ######################### ######
= = = = = = = = = = = =
A B C D E F H J K L M N
! ! ! ! ! ! ! ! ! !
! ! ! ! ! ! ! ! ! !
port 1-> 8 1 2 3 4 ! ! ! ! !
! ! ! ! !
port 2-> 1 2 3 4 8
Joystick pin diagram => 5 [4] [3] [2] [1] looking at back of \ / male connector 9 [8] 7 [6]
The 'fire' button (pin 6) is added by connecting joystick port pins 1 and 2 to pin 6 with diodes, solder each diode from (already wired) pins 1 and 2 to pin 6 (with the banded ends to pin 6).
On the PET the pin arrangement for the IEEE-488 port is:
1 1 1 1 2 3 4 5 6 7 8 9 0 1 2 = = = = = = = = = = = = ###### ################### ######### = = = = = = = = = = = = A B C D E F H J K L M N
1 - DIO1 9 - IFC E - REN 2 - DIO2 10 - SRQ F - GND 3 - DIO3 11 - ATN H - GND 4 - DIO4 12 - GND J - GND 5 - EOI A - DIO5 K - GND 6 - DAV B - DIO6 L - GND 7 - NRFD C - DIO7 M - GND 8 - NDAC D - DIO8 N - GND
IEEE-488 Device Connector Pinout:
+- ! ---- (NOTE: The pin order may look backwards ! ---+ but two references list it as such) ! 1 13 ! ! 2 14 ! ! 3 15 ! 1 - DIO1 9 - IFC 17 - REN ! 4 16 ! 2 - DIO2 10 - SRQ 18 - GND ! 5 17 ! 3 - DIO3 11 - ATN 19 - GND ! 6 18 ! 4 - DIO4 12 - GND 20 - GND ! 7 19 ! 5 - EOI 13 - DIO5 21 - GND ! 8 20 ! 6 - DAV 14 - DIO6 22 - GND ! 9 21 ! 7 - NRFD 15 - DIO7 23 - GND ! 10 22 ! 8 - NDAC 16 - DIO8 24 - GND ! 11 23 ! ! 12 24 ! ! ---+ ! ---- +-
1 1 1
1 2 3 4 5 6 7 8 9 0 1 2
= = = = = = = = = = = =
### ######################### ######
= = = = = = = = = = = =
A B C D E F H J K L M N
1 - System Ground A - GND 2 - TV Video B - CA1 3 - IEEE-SRQ C - PB0 4 - IEEE-EOI D - PB1 5 - Diagnostic Sense E - PB2 6 - Cass.1 Read F - PB3 7 - Cass.2 Read H - PB4 8 - Diag Tape Wrt. J - PB5 9 - TV Vertical K - PB6 10 - TV Horizontal L - PB7 11 - GND M - PA2 (CB2) 12 - GND N - GND
1 2 3 4 5 6
= = = = = =
###### ###########
= = = = = =
A B C D E F
A or 1 - GND B or 2 - +5v C or 3 - Motor (computer controlled +6v for datasette motor) D or 4 - Read line from cassette E or 5 - Write line cassette F or 6 - Cassette Switch Sense (monitors cassette play/ff/rew buttons)
An excellent source for PET compatible edge board connectors as, the 24pin centronics connectors (not to mention just about any other component) is DigiKey Corporation:
DigiKey Corporation 701 Brooks Ave. South Thief River Falls, MN 56701-0677
(800) 344-4539 www: http://www.digikey.com
Call or write and ask for a catalog!
The parallel and IEEE-488 ports both accept 12/24 edge board connectors with 156” contact spacing, the datasette port accept 6/12 connector with .156“ contact spacing.
Side Note: Digikey does not seem to have proper hoods (enclosures) available for the edgeboard connectors, which can make it quite a struggle to remove the buggers once connected. I have found that using 1.25” long by 6/32“ machine screws fit snugly in the side mounting holes, with a matching nut and lock washer it would make a good gripping surface away from the sensitive contacts. These parts can be easily/cheaply found at most hardware stores.
+---+ Washer and Nut
Mounting Hole !! !!!--------+
!! !!!--------+ Screw
+--+ !==
Edge Contacts ! !== Pins
This is a list of some of the many devices of the PET I am aware of, for many I only know of their existance not how they are installed or used.