Search found 430 matches

by Martin A
12 May 2019 21:21
Forum: NEW HARDWARE
Topic: CFX
Replies: 56
Views: 10515

Re: CFX

But it works fine when the RS232 board is not fitted? OK, I have found one issue. The machine's stable when in BASIC and running games. The machine boots into the CFX menu fine and as long as you enter BASIC within about 10 seconds everything is fine. If I leave it any longer then the machine will ...
by Martin A
12 May 2019 20:55
Forum: NEW HARDWARE
Topic: CFX
Replies: 56
Views: 10515

Re: CFX

Mmm, that’s odd. Martin, any ideas? The PAL on the RS232 is the usual 14L4. Looking at the pal-assem code for that in the phoenix manual: Pin 14 is the direction pin for the LS245 buffering the data bus Pin 15 enables the DART I/O ports, it's fully decoded so shouldn't clash with the CFX's I/O rang...
by Martin A
11 May 2019 20:43
Forum: HARDWARE
Topic: Resurrecting an MTX500.
Replies: 226
Views: 18244

Re: Resurrecting an MTX500.

That's the reason for the "?" in that post 8-)

TI's crazy naming convention :shock:
by Martin A
11 May 2019 18:17
Forum: HARDWARE
Topic: Resurrecting an MTX500.
Replies: 226
Views: 18244

Re: Resurrecting an MTX500.

YAY Progress, I'd be looking at the 6116 providing bit 0 of the video memory 6G maybe ?
by Martin A
11 May 2019 09:23
Forum: HARDWARE
Topic: Resurrecting an MTX500.
Replies: 226
Views: 18244

Re: Resurrecting an MTX500.

You can also feed the Y output from J12 pin 2 to a composite monitor or SCART TV. The signal needs to go through a resistor to form a voltage divider as the 9929 outputs a nominal 3v peak voltage, and composite 1v (on SCART at least) 470R is the resistor value I found "on the net". That to me seems ...
by Martin A
10 May 2019 23:09
Forum: HARDWARE
Topic: Resurrecting an MTX500.
Replies: 226
Views: 18244

Re: Resurrecting an MTX500.

I'm home now. I've programmed a GAL with the 3 ROM & 64K RAM JEB file from Andy's site, fitted it and the ROM select line is still constantly high. The address lines are active as is the _RD line but no ROM select. What's the logic used to generate the ROM select for ROM A? Maybe I'm missing someth...
by Martin A
10 May 2019 13:51
Forum: HARDWARE
Topic: Resurrecting an MTX500.
Replies: 226
Views: 18244

Re: Resurrecting an MTX500.

I don't know if these will help - its a set of WinCUPL files for a replacement MTX500 (or maybe 512) PAL using the ATF16V8
MTX500CFPLA.zip
(7.62 KiB) Downloaded 38 times
by Martin A
09 May 2019 23:35
Forum: HARDWARE
Topic: Resurrecting an MTX500.
Replies: 226
Views: 18244

Re: Resurrecting an MTX500.

If it IS the 1889, have a word with Andy.

When he put this page together he had spares of that.

http://www.nyangau.org/memotech/parts.htm
by Martin A
09 May 2019 23:32
Forum: NEW HARDWARE
Topic: System test rom/Board
Replies: 26
Views: 3000

Re: System test rom/Board

stephen_usher wrote:
09 May 2019 22:51
I take it that the test ROM contents can go on an EEPROM and go into the ROM A socket?
It should work fine as a stand alone 8k image replacing the A rom. It's completely self contained.
by Martin A
08 May 2019 21:12
Forum: HARDWARE
Topic: Resurrecting an MTX500.
Replies: 226
Views: 18244

Re: Resurrecting an MTX500.

Surely board connected into ROM B socket with a couple of flying leads to ROM A and ROM C would give all the lines needed to run a 32K ROM? Put the three ROM select lines through an inverter and use the ROM B and ROM C select output as two address lines. Then put all three inverted ROM select lines...