Several answers
Date: 1998-03-26 21:26:22

Hallo allemaal,

In this email I react on a lot of emails received yesterday. When I asked
my emailer to save all emails in one single file, I had no choice then to
accept that he saved it in alphabetical range. So my reactions may be a
little bit out of time .-)

Hallo Levente,

> Ps. Ruud, you are a Dutchman, aren't you?
Yes, I am.

> I remember, once you wrote something like "went to the moon" or a
> similar expression.
> I also remember a band (Culture Beat) who had a song 'Rocket to the
> Moon'......

I vaguely remember the band but certainly not the song. "Going to the moon"
means that something has been destroyed in some way. So if you blow up your
CIA, then it went to the moon.

Hallo Ethan,

> Traditionally, RS232 was implemented on PETs with either an IEEE488
> box (I have a couple) or a board that piggybacks into a ROM socket
> and taps R/W from somewhere (I have an ACIA board like that, too).

I think I have this IEEE/RS232 interface on paper somewhere, (PET revealed page 
157) but if it is the right one??? I don't think so. Please tell us at least of 
the used ICs. That could give us some more clues.

Hallo Andre,

> I once made an IEEE488 cartridge for the Atari ST ROM port, without
> tapping R/W. reading from a block of 256 addresses is outputting data
> on the address lines :-)

Smart, but costly. But this triggered my mind to produce the following idea
but based on your original concept. Replace the 6510 by a board with the
6510, a 74LS610/2, buffers, some glue logic and a bus to connect even more
hardware. In this way you can use your C64 as you use your CS/65 a pod for
your 1541. One question remains: how do you handle the clock signal? Is it
possible to use the 1541 wih a "processor" which is running asynchrone with
the onboard 16MHz. clock.

> To all: I haven't heard any comments on this page so far, what do you 
> think about it? Is it ok, should I trash it? (The web server is long up 
> again.)

Looked very good!!!

> .... Remember, the PET has _no_ NMI source.

?????? What do you mena with this?

Hallo Olaf

> Speaking of dutch people: is there anyone who can help me fix a few
> broken PETs that I have? I have a broken 8296 and a 8032 ......

Natuurlijk, geen probleem! Nou ja, geen probleem..... First we have to
determine how we can solve the problems in the best way. I cannot help you
with the 8296. One idea is to send the board to Andre and let him have a
look at it. But you have to sort that out with Andre himself of course. I
have a 8032 myself but with a faulty keyboard/6520 but that's no problem. I
don't own a 8050 but do have a an old 8250. The boards are the same.
Somebody mentioned that the only difference is the software. (FYI the board
of the new flat 8250 is completly different) So I least have the means to
start with the easy way of repair by exchanging parts. I do have a scoop as
well in case of the exchange doesn't work. AND.... (flash, flash, flash,
big bulb above my head) I have a little box which you simply clip on the
processor. The box contains one/two ROM(s) with diagnostics software. 
Anyway call me on 045-5630563 to see how we can arrange something.

Hallo John,

> Electron mobility in silicon is higher than hole mobility.  But that has
> nothing to do with the 1541.  The serial bus uses open-collector drivers
> for the outputs.  In the 1541, they use a 7406 (this is from memory - 
> might be wrong), which inverts the signals.  The lines are connected
> directly to the inputs, so they're not inverted (there's probably a
> series resistor or something to protect the PIAs, but the signal still
> doesn't get inverted).

NO, there is at least one 74LS14 gate between the connector and the 6522. I
can know this because I had to repair 3 1541s blown up by one person due to
not grounding his system.

> Why do they use open collector drivers?  So you can connect more than one
> device to the same wires.

YES, That's why you can connect more then one drive to your C64 and that is
at the same time the reason why they each must have their own address because 
there is no other way telling them. The software figures out which device 
actually is addressed.

Hallo Andrew,

> Is the above similar to Corel Wordperfect suite 8?

I don't know this version but if you mean that is a successor of WP 6.1 for
Windows then my answer is NO. My WP-editor can edit nothing else but ASCII-
text. It doesn't even know fat, underline, italic, tables and all that kind
of things. But it does know macro's and can handle up to 9 screens. The
total amount of bytes of all files are 192 KB. (compare with 6.1: 20 MB)

BTW, what about your address because of the CP/M cartridge?

Hallo Per,

> None of them do, so I guess my question should be whether it's
> possible to hook up an IEC device to an IEEE bus without actually
> ripping out the IEC interface and reprogram the drive ROMs. I want to
> have my cake and eat it too :) Am I right in thinking that the actual
> commands sent on the bus are if not identical at least pretty
> similiar?

If you have the right software there is nothing against hooking a IEC device to 
an IEEE interface. You only have to look at X1541.

>   Hmm, it shouldn't be too hard to get a 68HC05 to act as a IEC <->
> IEEE router.

No. I own 2 IEC <-> Centronics interfaces. Both use a 8039. In your case the 
problem will be the software again.
This reminds me of having a box labeled "Interpod". Does that sound a bell? It 
has an IEEE connector, two IEC connectors and a RS232 interface. 6502, 6522, 
6532, 6850 (=RS232). No docs :-(
Andres CS/65 is capable of using both interfaces so it IMHO it should be 
possible to downsize it to something like my INTERPOD but with that difference 
that most of the sourcecode is available.

Groetjes, Ruud

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