Re: catbox

Awesome..thanks for the reply.. Maybe I'll just get
one and try it out.. for 50$ can't really go wrong.

--- Philip Pemberton <lists@philpem.me.uk> wrote:

> andre wrote:
> > So I was looking at the Atari catbox which seems
> to
> > have been designed for people with no real
> electronics
> > background.... but 'many' posts just say to get a
> > hp5004a instead. I have tried to find more info on
> the
> > HP, but have not been very successful.
>
> The HP 5004A is a signature analyser. At its heart,
> it's a simplified 16-bit
> CRC generator -- it takes a stream of
> clock-synchronised input bits and feeds
> them into a shift register (an LFSR to be precise),
> which compresses the input
> down to 16 bits, and does it in such a way that a
> false input will cause the
> signature to mismatch.
>
> It has a clock gate as well - the clock signal you
> feed to the SA is ignored
> until START goes active, then data bits are clocked
> in until STOP goes active.
>
> > Looking at the
> > front of the unit, there does not seem to be a
> whole
> > lot of things to be able to set. So I am
> wondering,
> > using the Gravitar manual as an example, does the
> HP
> > manual clearly explain how to (for instance);
> >
> > a. TESTER MODE: SIG
>
> "Signature Analysis" mode. Pretty much all the 5004A
> does :)
>
> > b. TESTER SELF-TEST: OFF
>
> Well, the all-segments-on test display isn't that
> much use for troubleshooting...
>
> > C. PULSE MODE: LATCHED
>
> Not sure about this one.
>
> > D START: Negative-going edge trigger
> > e. STOP: Negative-going edge trigger
> > f. CLOCK: Negative-going edge trigger
>
> Sets the SA to trigger on the high-to-low edge of
> all those signals.
>
> > DBUS SOURCE: ADDR
> > BYTES: 1024
> > Enter address 0000 with the keyboard~(HP doesn't
> have
> > a keyboard?)
> > SET R/W MODE to PULSE and back to (OFF)..
>
> Looks like a RAM test to me... the CAT Box has the
> ability to feed a data
> pattern into the bus and probe the RAM. The
> signature analyser can't do this;
> it's a strictly passive device.
>
> In effect, the CAT box is a combined digital word
> generator (stimulus
> generator, pattern generator... whatever you want to
> call it), signature
> analyser and RAM/ROM tester fitted into a briefcase
> with a 6502 microprocessor
> to watch over everything.
>
> > and on and on.. How would I know what was a
> comparable
> > thing to set on the HP? The above are just
> examples of
> > things that I picked out that I can't find
> anything
> > remotely the same on the HP.. When people talk
> about
> > it, they make it sound retty simple to use on in
> place
> > of a CAT but it doesn't seem so... Is this all in
> the
> > manuals with the 5004a?
>
> The 5004 manual is online at
>
<http://www.gamearchive.com/General/Data_Sheets/HP5004.pdf>.
> There's plenty of
> other stuff about signature analysis about -- for
> instance
>
<http://www.gamearchive.com/Video_Games/Manufacturers/Atari/signatures/>,
>
> which provides lots of info on how it actually
> works.
>
> If you wanted to, you could probably build a
> signature analyser -- it really
> boils down to a few 74LS logic chips and some
> 7-segment LED displays. Though
> I'd much rather buy a used HP 5004 and put the time
> saved into troubleshooting
> the game board...
>
> Although at one point I was toying with the idea of
> making up a small-ish
> board that could be connected to an Atari game board
> to do most of the stuff a
> CAT box can do, only without the high cost of
> purchase. The project kinda
> stalled after a while -- too much to do, too little
> spare time to do it :(
>
> --
> Phil.
> lists@philpem.me.uk
> http://www.philpem.me.uk/
>
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Received on Mon May 12 09:16:05 2008