I am currently working on using my C-64 for a robotics project. What I need
is the voltages off of the power supply, and what pin they are coming from.
Please list them in COUNTER Clockwise order, starting from the bottom-most
LEFT one. Thanx!
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Category 3, Topic 13
Message 2 Mon Nov 13, 1989
DIGITAL.DOC at 22:05 PST
Ok, MG, Here they are...
u
7 6
1 3
4 5
2
This is looking at the connector from the open end. You may not have all the
pins listed. The normal ones are 2,5, 6, and 7.
Here's the pin out:
2 is ground
5 is +5VDC
6 and 7 should be 9VAC
If they exist, pins 1 and 3 are also ground
If it exists, pin 4 is also +5VDC.
Hope that helps...
<Doc>
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Category 3, Topic 13
Message 4 Fri Aug 03, 1990
C.GAMLOWSKI1 [Gamlowski] at 18:32 PDT
I am thinking of building a Cartridge switcher for my Sega Genesis game
Machine, like the Aprosand C64, but with more cartridge slots. Can anyone
help me. I've been told, but do not understand the following:
If the cartridges are digital you could do it by using a tri-state, non-
inverting buffer on each pin of the cartridge. It would probably take eight
IC's as I think they come eight on a chip, there are 64 pins per cartridge.
Tie the 64 enables for each cartridge together and connect to a selector
switch. Put all the outputs onto a bus going to the Genesis and shazam, you
select which cartridge you want by turning on the "enable" switch for the
cartridge you desire.
Later on he continues....
If you can't find which pin is the power, you only other choice is to disable
all 64 pins when you want to take the cartridge offline. This is certainly
not the best (cheapest) alternative but it would do the job. This also what I was talking about in my other message - a buffer on each pin would do the trick.
You can hookup as many cartridges as you want, just put them all in series on
the same cable that runs to the Genesis. Keep the cable short as possible to
help keep down any noise the cable might pick up. Run the power line
(assuming you can find it) from the Genesis to center pole of a rotary switch. Run a power line from the output of each switch position to each single cartridge. Now, by turning the selector switch, you turn on the power to cartridge it is connected to. The other cartridges are still connected to the Genesis by the cable, but since they don't have power going to them they (hopefully) won't affect the game.
Here are the part numbers I found, everything should be common enough for any
electronics shop to have them or something similiar:
Selector switch - Grayhill single pole, 10 position rotary #19001- 10UL
Ribbon cable - Beldon 64 conductor #9R228064
The 64 pin doesn't seem to be a common size, so you will have to go with a
bigger connectors and make them fit. They make little "keys" that fit into
unused pins. Where can I get 64 pin connectors (me writing)?
From the latest message...
The buffer you would want to use is 74HC244 - should be common anywhere for
about a dollar each. There are 8 buffers per IC with two enables (running
four buffers each). If you end up using them, I can give you specific pin-outs on how to wire them.
Okay now I'm writing....
With all said, does anyone have a step-by-step English translation of how to
build this gizmo?
Appreciated,
Paul David Gamlowski
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Category 3, Topic 13
Message 6 Mon Aug 06, 1990
C.GAMLOWSKI1 [Gamlowski] at 22:38 PDT
I found there is just One position (two contacts) with 5+ volts when metering
the Genesis cartridge port. So I guess I found the power... But still the
rest needs to be answered, ie. purchasing 64 pin (32 position female, male , and ribbon connectors), how to hook this up properly, and possibly putting in a
fuse like the Aprosand etc. Please help me Doc...
Highly appreciated,
Paul David Gamlowski
P.S. I know this isn't a Commdore Machine, but actually in a way it is since
the Genesis's games are programmed on an Amiga and the Sega Master System and
Power Base Converter for the Genesis is similiar (from what I hear) to the C-
64, especially in their ability to use sprites. Again Highly appreciated....
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Category 3, Topic 13
Message 7 Tue Aug 07, 1990
DIGITAL.DOC at 21:15 PDT
Ok Paul,
I'm back with a little help anyway <Grin>! (You sure do come up with tough
questions!)
Let me answer one of the last questions first: the fuse. The fuse goes in the
5 volt line between the computer and the expansion ports. The value of the
fuse (amperage) I'm not sure of since I'm not really familiar with the
Genesis equipment. If I remember right, the C64 would prefer it if the cartridges did not draw over approx one half amp total.
Tougher questions next....
You asked for an english interpretation of the material you posted earlier.
I'm not real sure I can do that, but let me give it a try and you can ask
questions about the explanation, if need be.
Let's try the tri-state buffers first. <Taking a deep breath!>
For starters, look at the buffers as if they were switches. They do a lot
more than that, but lets start slowly. The "enables" that were talked about
are like the handles of a light switch: in on position, the switch is on and
the light operates. In the other, the switch is off and the light doesn't
operate. The fact that the other side of the switch always has power is
irrelevent. In the light switch analogy, we provide a physical action
(flipping the switch up or down) to enable or disable the light (enable =
on). With the buffers, we provide an electrical signal to do the same job
When the appropriate voltage is applied to the enable inputs on the buffer
chip (either +5 or ground), the chip "turns on" allowing the computer and
selected cartridge to talk. When the opposite voltage is applied to the
enable inputs of the buffer, the computer can not tell that the cartridge is
even there. To use this method, you would have to buffer each pin of each
cartridge you wanted to have connected to the expansion device.
This leads to the explanation of the term "Tri-state". The first two states
are the ones everyone thinks of when talking about computers:
Ones (usually +5 volts in this kind of equipment) and Zeros (usually 0
volts or ground in this kind of equipment). The third state is the one
alluded to in the previous paragraph: Not there. It is the electrical
equivalent of disconnected. Normally, the inputs to computer chips draw a
small amount of current from the device feeding them. Connect enough of
these together to a single output device, and you will overload it causing
premature failure.
Output pins normally attempt to be either +5 volts or ground. On the common
bus lines of most computers, (address and data, mostly) many outputs and
inputs are connected to each other. If one chip was trying to output a
ground, and another chip was trying to output +5 volts, we have a severe
problem!
Hence the development of the tri-state buffer. These devices do one of two
things: When enabled, they are virtually invisable to the devices connected
to the input and the output...like a light switch in the "on" position. When
disabled, the inputs and the outputs can not see each other at all....like a
light switch in the "off" position. This prevents loading down the source
(usually the computer). This is a better situation than just shutting off
the power to the cartridge, because the internal circuitry - even when powered
down - can place a load on the line.
The ideal situation is a switch that both enables a set of tri-state buffers
on the pins of the cartridge and applies power to the cartridge at the same
time.
Keeping the cable short:
Most computer type equipment operates around other electronic equipment which
works at relatively high frequencies. (ie TV's, Monitor's, disk drives, etc)
Every piece of wire acts like an antenna. It picks up some "interference".
The amount of this interference is directly proportional to the length of the
wire. Therefore, shorter wires are better wires!
64 pin connectors:
Can't help you a lot in this area. I haven't run across any lately either.
However, if you can get the address to the Beldon Corp, they are a very
likely source. They are the major producer of wire and connectors and have a wide stock. Sorry I don't have an address handy.
The remaining info that will be needed before this device can be built is:
A pin out of the Genesis' connector being used.
A source of the connectors.
A better idea of your skill with soldering, etc.
Perhaps other GEnie users can come up with the first two! The answer to the
third will be a big factor in deciding whether the device can be built or
not. <Grin>
Hopefully, I answered all your questions, Paul. If there's something I
missed, let me know, and I'll try to get the answer.
Looking forward to hearing from you.....
<Doc>
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Category 3, Topic 13
Message 9 Fri Aug 10, 1990
C.GAMLOWSKI1 [Gamlowski] at 23:07 PDT
Thanks Doc, this is greatly appreciated.
What happens if I use a meter to test what contacts are hot and grounds? Is
this safe or unsafe? Also I didn't think I would need to know the pinouts of
the Genesis, since buffers would be used. My dad works at General Motors at
Delco Electronics, he just recently took a new class on sophisticated
soldering, so there shouldn't be any problem their. And finally I may find
the connectors at Electronic Parts Supermart in Santa Maria, California, just
about 35 miles from where I live (being Lompoc).
Thanks again,
Paul David Gamlowski
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Category 3, Topic 13
Message 10 Sat Aug 25, 1990
DIGITAL.DOC at 20:39 PDT
Paul,
Sorry for taking so long to get back with the answers to your questions.
I've been a little tied up lately.
Yes, you may use a meter to test the contacts for power and ground. However,
this is not a fool-proof method. Some pins are normally held at specific
levels by the equipment either as a signal to the cartridge or just because
they're inputs and are waiting for a signal from the cartidge. I would
expect that you will find a number of lines that appear to be power lines,
but are not. It is typical for pins awaiting inputs to be held at approximately the power supply voltage.
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Category 3, Topic 13
Message 11 Sat Sep 01, 1990
C.GAMLOWSKI1 [Gamlowski] at 17:31 PDT
Thanks for help Doc. But I found it to be too expensive if not bulk
manufactured. Oh well, maybe some with the $$$ will market such a thing as
for me I'm just the average joe middle class man.
Thanks anyway,
Paul David Gamlowski
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Category 3, Topic 13
Message 12 Wed Sep 05, 1990
DIGITAL.DOC at 20:10 PDT
OK Paul,
Such is the problem sometimes with good ideas! <Grin> Always glad to
