Search found 459 matches

by Martin A
28 Jul 2020 19:02
Forum: GENERAL DISCUSSIONS
Topic: MTX 512 (debugging thread)
Replies: 56
Views: 9085

Re: MTX 512 (debugging thread)

Just for reference, those rams are 150ns, not 15. Back in the 80s, 15ns ram was the sort of stuff you'd find in a Cray mainframe. :o

When the MTX was built, 200ns for the rams would have been normal, so 150ns is faster than required definitely not too slow.
by Martin A
20 Jul 2020 19:33
Forum: HARDWARE
Topic: No picture.
Replies: 89
Views: 3516

Re: No picture.

I can see from the photo that there'sa 32k ram board in there. To might find the main board easier to move if you take the extra ram out first.
by Martin A
25 Jun 2020 19:55
Forum: OFF TOPIC
Topic: Another Home-Brew - Z180
Replies: 64
Views: 11510

Re: Another Home-Brew - Z180

It's a great feeling when that happens. Well Done :D I've checked the Z180 board I did for the MTX plus, that's got a 12mhz clock on it so I suspect I ran that clock doulbed. It's a long time since I played with it, though I do remember trying all sorts of clocks, I think it was more stable at 12 do...
by Martin A
20 Jun 2020 13:49
Forum: OFF TOPIC
Topic: Another Home-Brew - Z180
Replies: 64
Views: 11510

Re: Another Home-Brew - Z180

Bill B wrote:
20 Jun 2020 11:21
Martin A wrote:
19 Jun 2020 22:09
Sheesh that's a lot of work to get the CPLS programmed!
Since the whole project is just a pass-time anyway, what does it matter :roll:

Besides, I learn stuff along the way.
And the learning is the important thing really.
by Martin A
19 Jun 2020 22:09
Forum: OFF TOPIC
Topic: Another Home-Brew - Z180
Replies: 64
Views: 11510

Re: Another Home-Brew - Z180

Sheesh that's a lot of work to get the CPLS programmed!

But it's done now :D
by Martin A
31 May 2020 19:56
Forum: OFF TOPIC
Topic: Another Home-Brew - Z180
Replies: 64
Views: 11510

Re: Another Home-Brew - Z180

If you've got an older PC with a parallel port, you could consider building a byte blaster. The circuit for those is on the net, and seems to be 2 chips and some passives.
by Martin A
01 May 2020 20:25
Forum: NEW HARDWARE
Topic: SPX - Large capacity, read only, "disc" system
Replies: 2
Views: 935

Re: SPX - Large capacity, read only, "disc" system

Interesting idea. :D The chips are pretty cheap, of the order of £1.20 each in 10's. Putting 2 on won't break the bank! (They are much, MUCH cheaper than parallel flash which costs about that for 1/2 a meg, and imagine the board size and decoding required for 32 of those!) Adding the extra output po...
by Martin A
01 May 2020 14:37
Forum: NEW HARDWARE
Topic: SPX - Large capacity, read only, "disc" system
Replies: 2
Views: 935

SPX - Large capacity, read only, "disc" system

If anyone remembers Memofest 2018, there was a strange 8 pin chip that found it's way into the photo of the NFX network card. I think I mentioned at the time that it was an 8 meg serial flash, and capable of taking an entire CPM partition. I've now managed to get something build to test the idea of ...
by Martin A
24 Apr 2020 11:49
Forum: OFF TOPIC
Topic: Another project completed
Replies: 2
Views: 777

Re: Another project completed

The bike computer has had a couple of upgrades, the backlight is now enabled and the software now includes a speedo. I managed to avoid doing any math by using tables and pre-rendered images of the speedo. Bike upgrade.jpg The power LED resistor got upped too, it was uncomfortably bright in poor lig...
by Martin A
19 Apr 2020 21:48
Forum: OFF TOPIC
Topic: Another project completed
Replies: 2
Views: 777

Another project completed

Nothing to do with the MTX. (well almost nothing see below) Question 1: What do you do when the screen/trip computer on your exercise bike dies ? The answer, build a new one from scratch of course! Question 2: Do you do the sensible thing and use a 20 or 28 pin microcontroller and SPI display The an...