THE RHOTRON BUSSYSTEM by Richard Karsmakers
The German company Rhotron GmbH has recently developed a full
range of expansion cards for the Atari ST series. In this
article, I'll have a look at them and tell something about the
specifications, prices, etc.
Firstly, Rhotron offers a so called Rho-PC (price: DM 3498). This
is an Atari with PC system case, which includes two disk drives,
a blower, all nessecary cables and the Rhotron bussystem.
The actual bussystem leaves space for 8 expansion cards to be
plugged in (the bussystem costs DM 298 seperately). The bus is
built up around the VME-like 96-pins, which is a direct extension
of the MC68000 processor-bus. That's why all signals from the
68000 are directly available, like byte-,word-, longword-,
synchronous-and asynchronous instructions. All interrupt levels
as well as DMA are supported as well.
The bussystem offers the user +5V, +12V, -12V and +5V accumulator
voltage. For most expansion cards, +5V is needed so that you will
be able to work with the standard Atari power-supply. The
bussystem principally offers you a potential memory maximum of 11
MByte, a Watch-Dog timer and Addressdecoder-RAM.
The Atari PC case is also sold seperately at DM 268.
One of the most stunning things to be available as expansion for
the bussystem is a 2 Mb dynamic RAM card. Unlike the RAM on the
Atari motherboard (which gets about 50% of processor-time), this
RAM gets almost full processor time (so almost 8 Mhz). Rhotron
uses RAM 41256-150 chips on that card (quantity is 64). The 2 Mb
RAM can be installed by software as RAM-disk, expansion RAM or
printer spooler. The card costs DM 1198 with RAMs and DM 698
without the RAMs. Not a bargain, but definately worth buying for
those of you that are into serious applications and lots of
Next on the list if the WFS Controller card (DM 1798) that allows
link-up with three floppy disk stations (either 3½" or 5¼"), 2
hard disk drives and one 20 Mb streamer (backup for harddisks).
This card e.g. enables the user to copy an entire harddisk to the
streamer in 17 minutes without having to wait: The computer is
normally available for other tasks. The maximum capacity of the
hard disk drives may be 2x64 Mb.
Rhotron also sells the WFS Controller card with 20 Mb harddisk
for DM 3298, or with 20 Mb harddisk and 20 Mb back-up streamer
for DM 5998.
Then there's the EPROM-programmer from Rhotron. It sells at DM
498 and can work with the following EPROMs: 2532, 2732, 2732a,
2764, 2764a, 27128, 27128a, 27256, 27256a, 27512, (27513, 40 pins
EPROMs), 2864 and 58064. This card comes with an additional card
with two Textool sockets that is attached to the main whole by a
40 cm flatcable (to allow the EPROMs to be inserted, etc. outside
the computer). Most regular options are available with the
software, such as file read, file write, intelligent programming
mode, quick programming mode (5 ms), show memory and more. Of
course, both byte-and word-wise PROMming is possible.
Rhotron also offers several Digital-Analog and Analog-Digital
converters, with different bit resolutions (8,10 and 12 bits).
Describing them all would lead too far in the context of this
article, but I have hereby included a small list:
Sort: Bits: Converting time: # of Channels: Price:
D/A 12 1µs 2 DM 438
A/D 8 110µs 8 DM 268
A/D 12 35µs 16 DM 898
D/A+A/D 12+10 1µs+25µs 8 (A/D) DM 848
The Multifunction-card that Rhotron offers costs DM 348 and
offers you a real-time clock (with a precision of 1/1000 sec)
with battery-backup, 28 I/O ports, a 24 bit timer, a buffered
Centronics port and space to stick on 4 RAM 43256 (128 Kb) or 4
EPROM 27512 (256 Kb).
At DM 228 (without accu buffering) or DM 268 (with accu
buffering), Rhotron offers a RAM/EPROM card. It can contains a
maximum of 4 RAM 43256 (128 Kb) or 4 EPROM 27512 (256 Kb), like
the card I mentioned above. One very nice characteristic of this
card is the fact that all RAMs (if sticked on) are battery-
backed. This creates easily programmable 'EPROMs'. This makes
this card great for people who often test out EPROM-resident
Less interesting cards in the scala that Rhotron offers are the
Parallel I/O card (which sells at DM 298 and offers e.g. 56 I/O
lines), an Experiment-card (sells for DM 698), an IEEE 488 (IEC)
bus (DM 698), a clock card ( a battery-backed clock for DM 138),
and additional power supplies (when the bus systems want more
Rhotron offers only ready-made products now, and can be reached
at the following address:
The text of the articles is identical to the originals like they appeared in old ST NEWS issues. Please take into consideration that the author(s) was (were) a lot younger and less responsible back then. So bad jokes, bad English, youthful arrogance, insults, bravura, over-crediting and tastelessness should be taken with at least a grain of salt. Any contact and/or payment information, as well as deadlines/release dates of any kind should be regarded as outdated. Due to the fact that these pages are not actually contained in an Atari executable here, references to scroll texts, featured demo screens and hidden articles may also be irrelevant.