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Commodore PET Projects
- petSD+ |
petSD+
Introduction
Commodore PETs initially used compact cassette tape for loading and
saving programs and data, later machines used floppy disk systems such as the
8250 twin DS/QD 5.25" disk
system that I obtained with my PET, shown in the photo above. The
8250 uses full height drives and a format unique to the PET -
the drive cannot even read or write disks from other Commodore
disk systems such as the
1541.
Nowadays, there are a number of floppy disk hardware
emulators, such as the
HxC
Floppy Disk emulator, that can be used to replace "standard"
floppy disk devices based on the
Shugart interface. The
non-standard nature of the PET floppy disk system means that
there are a very limited number of options available for the
PET, including petSD+ designed
by Nils Eilers. (Some other options are described on my
petSD+ Alternatives page.)
Quoting from Nils' webpage,
"A petSD is a modern mass storage solution for Commodore PETs
with an IEEE-488-bus. It can be used instead of and alongside
vintage floppy disk drives. The petSD makes file sharing between
the PET and the PC easy by using standard SD cards for storage."
Further technical details can be found on my
petSD+ Hardware page.
Note: initially, petSD+ was not designed to be used
with
devices equipped with a Commodore serial bus such as the
Commodore 64, there were already a number of compatible devices
available such as MMC2IEC,
SD2IEC or uIEC and Nils had not envisaged anyone wanting to use
petSD+ with serial bus devices. However, after one user asked Nils if
it were possible, Nils included an IEC option in the
firmware - see here for details.
petSD Availability - 2015 (as
petSD+ Version 1)
Although my initial interest was driven by my desire to get a petSD for myself, with Nils' permission,
I am now in a position to make petSD+ available to anyone else
who might be interested. (You can read about how I got into this
and the current status of petSD+ on my
petSD+ History page.)
Prerequisites
In order to use petSD+, or indeed, any IEEE-488 disk drives,
the PET/CBM computer must have a BASIC 2 or BASIC 4 ROM, the
earliest PETs with BASIC 1 do not support IEEE-488 disk drives
unless the ROM is upgraded to a later version - preferably BASIC
4.
The PET/CBM boot up string can be used to identify the BASIC
ROM being used :
|
Banner Text |
BASIC ROM Version |
| ***
COMMODORE BASIC *** |
Original (BASIC 1) |
| ###
COMMODORE BASIC ### |
BASIC 2 |
| ***
COMMODORE BASIC 4.0 *** |
BASIC 4 |
Constructability
petSD was designed to be constructible by the
average electronics hobbyist, and one of the design
goals was to be able to use through-hole-technology
(THT) components, rather than surface mount chips.
The one exception was the FT232RL USB-serial-adapter
for which a THT equivalent was not available. The
USB - serial adapter has been dropped from the petSD+
design, the only surface mount component remaining
is the SD card reader.
Assembly of the petSD+ kit is described on the
Assembly page. When
I asked for input on the prospective supply options, based on the limited number of responses, supplying a kit of
parts seemed to be the most popular choice. I decided that I
would
make kits available, as well as pre-assembled units for folks who
need one. In practice though, once the kits and pre-assembled
units became available, the majority of people wanted a
pre-built one.
Kits of parts and fully assembled petSD+ devices are available for purchase :
Please see the Ordering page for details
petSD Availability - 2018 (as
petSD+ Version 2)
A modified version 2 petSD+ has now been designed by Nils,
read the details of the modifications
here.
The first shipments of Version 2 will be by the end of
January 2018
References :
Nils
Eilers petSD home page
Donald's internet shop
The Vintage Computer Forums
-
petSD thread
Credits :
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