Subject: Re: Synertek 6507

From: "Dwight K. Elvey" <[email-masked]>
Date: Wed Mar 12 19:59:00 2003

>From: "Jim Kearney" <[email-masked]>
>
>>  This is what Eric Smith tells me as well. As I told
>> him, it doesn't make much sense. The board has a 6502
>> as well as the 6507 with the data lines tied together.
>> I guess they could use opposite phases or something.
>> I was tracing down the sync signals for the video
>> and they seem to be coming from this part??
>> I do have a schematic someplace but I haven't located
>> it yet.
>>  Now I have a mystery to solve?
>
>Possibly it's a variation of the Lancaster TVT (Cheap Video) design?
>
>What is it?
>

Hi
 Again, just what Eric said. It is for a KTM-2.
This is Synertek's keyboard/video board.
Dwight

---

From: "Jim Kearney" <[email-masked]>
Date: Wed Mar 12 20:47:01 2003

> This is Synertek's keyboard/video board.

Neat!  I really wanted one of those for my SYM-1 way back when.  As I was a
poor high schooler in 9179 I managed with a surplus keyboard scanned by
software and some kind of serial video terminal card that I think I got from
Mouser.

For some reason Eric's post didn't come through here, but it sounds like
we're on the same wavelength.

There is a page about it in my Synertek catalog, but no schematics or much
detail.  The text says "The design of the KTM-2 incorporates 8 MOS-LSI
integrated circuit chips, including two dedicated microprocessors.".

The picture is not quite sharp enough to make out, but it _looks_ like two
PIAs on the left to scan the keyboard matrix, then the two microprocessors,
then a couple of ROMs on the right, with smaller ICs mixed in.  If that's
the case, then there is no CRTC, and it's probable that the 6507 is acting
as the address and timing generator for the video.  The text sorta supports
this theory in that it says "More features are available at lower cost than
if a CRT controller chip or other approach had been used."

If you want a scan of the page I can send you one (tomorrow).

---

From: "Heinz Wolter" <[email-masked]>
Date: Thu Mar 13 09:43:44 2003

> >>  Now I have a mystery to solve?

I have an old Voelker-Craig terminal that uses this video
generation scheme. The Design uses two (count em) two
6502s, but only one runs rom code. The other steps through
a few 2114s as video ram. add a latch, shift register - voila video.
Think of the 6502 running on an inverted E clock with some
bits used as a rather expensive (even then) binary counter.
I would have used 74LS393s ;) Using some low order bits
to address ram while using higher ones for H and V sync would work.
Strangely, the whole system was clocked from a 4x colourburst xtal:)

> >Possibly it's a variation of the Lancaster TVT (Cheap Video) design?

Cheap video actually used  the CPU and an ISR to generate video, right?
This two CPU design didn't. Somehow they avoided  the usual vram muxes-
maybe the 2nd 6502 clocked a read out of vram, and write to the shiftreg ;)

Interestingly, the University of Waterloo Computer Systems Group designed
a little board that had a 6502 ~and a 6809, an LS123 and a switch - plugged
right into the 6502  socket on the PET 8032 mainboard to allow the proto
SuperPet (later SP9000) to run real languages on 96K of  16K Dram and
bank switched roms. Later Superpets had a Synertek 6551 uart and
copyrighted "poems" burned into obscure Harris fuse proms to prevent
easy copying of the hardware. Both CPUS were essentially tied together
(ie A0 on 6502 to A0 on the 6809 etc) - the switch held one or the other
CPU in reset under manual or reg. control. Of course some finagling was
required with ROM selects to allow each CPU to run only it's ROM.
FLEX or OS-9 would have been nice on this instead of Commodore's ugly "DOS".
Still, with a real baby-PDP-11-ish 6809 CPU with 16 bit index registers and
good addressing modes, the CSG  was able to miraculously offer APL, and
structured "Waterloo" flavours of Fortran, Basic, Cobol, Pascal and ASM
written in WSL - a C-like Waterloo Systems Language. These products
were later offered by Watcom for the Cemcorp Icon running on an early
186 based QNX system, and IBM PCs in early 80s. Watcom for quite a
while held speed records for their excellent PC/DOS  C  and Fortran
compilers which now updated and offered as openware- seeopenwatcom.org.
Watcom was bought by Sybase to capitalize on it's SQL-Anywhere product
and dropped other language  compilers/interpreters.
H