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· Hardware
#MousePort2:FAIL
11 messages in this thread
I am using (trying to, anyway) Superbase, the fancy database system from
England. This gem uses a dongle, a small device with two resistors and a
diode inside, that attaches to mouse port number two. The computer is
supposed to be able to read the number two port, do arcane things
to/with/at the dongle, and determine (A)yes it's there, and proceed to run
the program, or (B)no it's not there, and crap out. Well, aside from the
issue that on a GOOD machine, superbase elects to inform you that the
damngle isn't there and quit (like after you've just finished a file
definition, every time) I now have one Amiga that will not run Superbase at
all — superbase insisting that the damngle isn't there, and quitting.
Mouse port two on this particular machine will operate either a mouse or a
joystick with MarbleMadness, so I have a fair degree of confidence in the
integrity of the digital signal lines on the port.
The Hardware manual says that linear reads are done by comparing a state
of charge on a capacitor thru an unknown resistance at the port during
retrace. Ah-ha, said I. A comparitor, eh? inside the Amiga, I found a
TLO-84, which I told myself, could indeed be used for such and at the rates
indicated in the manual. I looked at every other chip in the system, and
they all be digital, so… I chopped out the olden one, carefully attached
a socket in it's place, and… no difference. I give up. The hardware
manual is less than helpful, I don't have schematics, and I'm pretty well
stalled. Can someone tell me which components are involved in the mouse
port number two analog read? or suggest another potential problem that
would cause the combination of symptoms seen here?
To be clear, the dongle and Superbase are fully functional on my other
machine, and used to work on this one. I took it up north for Xmas and
tried to show my mother ( a computer buff) the database — I think at that
time, many thousands of volts of static entered the AMiga via the dongle,
which I attached then, entirely without my permission. The static, that
is. I'm not entirely dead, as the other AMiga will run superbase (with it's
attendant auto-crashes at various times), but I find it extremely upsetting
that one of the machines is ill. Thanks in advance, –Ben–
Its the PAULA at U4E. Pins P1X – 35, P1Y 36. The digitals go
through an 74LS157 at U1M. Hope this helps
thanks john — theres analog comparitor circuitry in there, eh? it figures.
Connect the outside world to an LSI, hard to get, expensive device. yechh.
Thanks, though. –Ben-
I imagine the method of A-D conversion is the same as it was on the 64,
charge an external cap, and count the time from vertical retrace. When the
charge on the cap reaches a value determined by an internal comparator,
stop the count. Though it isn't pleasant when a VLSI chip goes, it should
be remembered that these chips are part of the reason we have such an
advanced machine.
I imagine the method of A-D conversion is the same as it was on the 64,
charge an external cap, and count the time from vertical retrace. When the
charge on the cap reaches a value determined by an internal comparator,
stop the count. Though it isn't pleasant when a VLSI chip goes, it should
be remembered that these chips are part of the reason we have such an
advanced machine.
Its the PAULA at U4E. Pins P1X – 35, P1Y 36. The digitals go
through an 74LS157 at U1M. Hope this helps
The pot inputs (the analog pins) are read by Paula. Sorry.
I'm sorry too. But thanks for your help. Now, I guess I have to get a Paula
chip. Let's see how good CBM is with part requests. Onward! –Ben–
The pot inputs (the analog pins) are read by Paula. Sorry.