Several answers (2)
Date: 1998-03-28 07:21:10

Datum: 28-03-98 7:17 
Onderwerp Several answers (2) 
Adres:  Aan: c64-maillist <> 
Hallo Ethan,

> The Portmaker itself has an empty ROM socket for the displaced ROM, a 68B50,
an empty socket for another 68B50, line drivers, and for select logic: 'LS21,
'LS393, 'LS30 and an 'LS139
                               _  ___
The three jumper leads go to R/W, IRQ, and Phi2 clock.

Got it. In this way you can use this model in every PET or CBM. They don't use 
all the same kind of expansion connectors (pinouts / place on the board)

The power rating is unusual: 115/230V 50-400Hz 4W.  I've never seen equipment
rated to 400 Hz before. 

Join the Navy and you will see more then enough :-) I do not know the history 
behind it but for one or another reason all the weapon computers and other high 
tech stuff on board of our naval ships and submarines use 400 Hz. Using a 
transformator on a higher frequency is no problem. The trouble is that your 
power output is not as good as you expected. (remember: transformator = coil)
Using a European trafo in the US is no problem, the otherway around is.

One has chips as new as 8310, the other 8009.  The newer one has an AY-3-1015
UART, but is otherwise identical. 

Both UARTs are identical and compatible with the CPD1854 of RCA. I once used 
one of these for an article about a RS232-tester in Elektor/Elektuur. Do me a 
favour and look how they connect pin 5..12 and 26..33 to the databus  of the 

If I were making one from scratch, I'd probably wire a 6551 onto an adapter
board and stick it in a ROM socket with little or no decoding.  Only when
I was using my PET every day did I worry about how much ROM space I had
(MicroMON, BASIC AID and the ROM PET Rabbit).  I only ever used 8K out of 12K.
Even a dual 6551 board isn't too difficult to wire up, if you clobber the
whole 4K socket.

You'll need at least an extra RW-line. (unless you use Andres idea)

I have a dream for my Portmaker: in my copious free time, port the C64 PPP
stack to the PET and hook my PET up to the Internet.  If only someone made
an Ethernet card that was easy to hook up to a 6502...

Some people managed to realise their dream. Grap your chance and be one of them!

(And then share the results wit us :-) )

Hallo Andre,

> I think the 6510 with 2 MHz (because of the MMU 74ls610 delay you 
> need a faster CPU .....

That's another reason why I intend to use the 612. You refer to the latch 
needed for the 610. You must see the 612 as a big, on the fly programmable, PLA.

> ..... then you can also take 65sc816 or such a beast for it - although the
> MMU solution is _much_ more elegant :-)

I agree more and more to this point of view as well, certainly with the 6510 in 
mind. My idea is to add only the 612 to a C64, then add one to my 8032SK end 
finally replace the 
6502 by a 65816.

> The NMI line of the CPU is only connected to the expansion port of the 
> 8032 (see your schematics on funet

You mean that it isn't used like with the c64. But that is quit understandeble 
(???) as the C64 emulates the 6551 and therefor the timing must be as precise 
as possible. With a real 6551 (or 16550) there is no need for this precision. 
IMHO there is nothing to worry about :-) (Or did you mean something else?)
> - BTW could you please upload a version
> where the drawing color is not transparent? Netscape prints transparent
> on white -> completely white :-( The 3008 schematics is ok.)

The 3008 is generated by Marko and is just a 2-color GIF-file as is the 8032. I 
noticed these problems with the GIFs of the 1541s working with NS on HP-Unix. 
After downloading them I had no problem printing them on my PC.
> The 4032 machines (with the upgradable-to-8032 board? are there ...

This is a point of confusion for me as well. I never saw a 4032 so I don't know 
for sure how they look like. But I thought they looked like a square 8032. (The 
SK looks like the 8296 and B700 ie. rounded case, turnable monitor). I lately 
received SCHs from Chris Happe (Canada) for the 4032/8032.  These  apply IMHO 
to the boards used in the 8032SK as they have all those wires and markings 
reffering to 40 and 80 columns.

> Ruud, are you sure that in your PET 3008 schematics PIA1 CB1 as well
> as VIA PB5 are connected to VIDON,

> which is controlled by PIA1 CA2?
CA2 controls the graphic-mode. (For those who don't know the PET, graphic-mode 
= using "funny" characters in stead of ASCCI. On the C64 you use the shift key 
for this. The PET has no real grphic capabilities at all.)

> I assume the two should be connected to TVV (vertical sync), right?
3008 NO, For the 8032, 8032SK and 4032 YES. (4032: see remark above)

> TVV, but I remember that I had to patch a certain game
> that worked on our 3032 but not on the 4032! ....
Maybe my previous remarks are the answer to this problem.

> Can anyone with a real machine confirm that please?
See remarks above :-)

Groetjes, Ruud

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