Search found 457 matches

by Martin A
25 Jun 2020 19:55
Forum: OFF TOPIC
Topic: Another Home-Brew - Z180
Replies: 64
Views: 9783

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: 9783

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: 9783

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: 9783

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: 670

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: 670

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: 581

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: 581

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...
by Martin A
03 Apr 2020 21:36
Forum: PROGRAMMING
Topic: Coding Challenge
Replies: 4
Views: 728

Re: Coding Challenge

Martin, I like the "PUSH HL / LD HL, value / EX (SP), HL" sequence. Not seen that before. I stole that from the MTX rom :lol: It's at #00BC .pend 0089 E3 EX (SP),HL 008A F5 PUSH AF 008B 7D LD A,L 008C E6 70 AND &70 008E 67 LD H,A 008F 3A D2 FA LD A,(PAGE) 0092 E6 8F AND &8F 0094 B4 OR H 0095 32 D2 ...
by Martin A
03 Apr 2020 14:44
Forum: PROGRAMMING
Topic: Coding Challenge
Replies: 4
Views: 728

Re: Coding Challenge

OK, totally untested, here's my first take on the re-entrant version: The only thing I know for certain is it builds ! Z80 Cross assembler V1.77 Source File MTX.Challenge Build 1 Pass 2 FAD2 page equ &fad2 0000 pageport equ 0 .farcall2 0000 F5 push af ; save the original af value, exit will need it ...