Search found 406 matches

by Martin A
14 Jul 2019 18:09
Forum: GENERAL DISCUSSIONS
Topic: MTX 512 (debugging thread)
Replies: 48
Views: 922

Re: MTX 512 (debugging thread)

I'm no expert on the power supply, but circuit diagram http://primrosebank.net/computers/mtx/repairs/regs/mtx_power.htm shows that : The TIP2955 is part of the +5 supply, not the -5. The -5v is derived from the -v supply (-12 ???) using the resistor R60, Zener diode ZD3 and capacitor C49. I would gu...
by Martin A
09 Jul 2019 19:34
Forum: MEMOFEST 2019
Topic: A bit early.
Replies: 7
Views: 295

Re: A bit early.

Andy's volunteered, well done Mr K !

See the post on Facebook for the date vote.
by Martin A
09 Jul 2019 19:17
Forum: PROGRAMMING
Topic: Bootstrap and boot blocks
Replies: 79
Views: 983

Re: Bootstrap and boot blocks

Bill B wrote:
09 Jul 2019 09:25
CFX Fuzix now running on MEMU :)
Nice one!
by Martin A
07 Jul 2019 18:21
Forum: GENERAL DISCUSSIONS
Topic: MTX 512 (debugging thread)
Replies: 48
Views: 922

Re: MTX 512 (debugging thread)

It look to me like the pattern has a repeat of 64, which would normally suggest the A6 address line might be involved.

Of course Texas labelled the VDP backwards, so maybe check AD1 for shorts and such ?

AD1 goes to the VRAM at 7G so that could be a suspect.
by Martin A
06 Jul 2019 20:05
Forum: NEW HARDWARE
Topic: ROTT 1600
Replies: 1
Views: 51

ROTT 1600

I've basically finished putting the extra components onto the memory board I build for Fuzix testing. It's time to introduce the ROTT 1600k memory board. rott 1600.jpg Currently fitted is a CFX style 16 bit IDE interface 2 x 512k srams, of which 448k can be seen from basic and 720k in CPM. (making 5...
by Martin A
05 Jul 2019 12:20
Forum: PROGRAMMING
Topic: Bootstrap and boot blocks
Replies: 79
Views: 983

Re: Bootstrap and boot blocks

I've finished wiring up a memory expansion with a full complement of RAM available in CPM mode. Which means Fuzix is now booting on my MTX512 :) There's none of the display issues seen on the MTXplus either. Fuzix booting.jpg It's only reporting 15 memory banks, so is seeing 720k, of which 672k is a...
by Martin A
29 Jun 2019 19:37
Forum: PROGRAMMING
Topic: Bootstrap and boot blocks
Replies: 79
Views: 983

Re: Bootstrap and boot blocks

The MTXplus will decode the MSX VDP ports as well at the MTX ports, so if you're designing V9938/V9958 only modes you can use ports 98 to 9B. (or 01,02 9A and 9B) The MTX plus itself has 2 different versions of CPM boot rom. The mono version uses text 2 and software scrolls. The colour version uses ...
by Martin A
28 Jun 2019 23:03
Forum: PROGRAMMING
Topic: Bootstrap and boot blocks
Replies: 79
Views: 983

Re: Bootstrap and boot blocks

It's interesting that the CMOS/NMOS issues we've found were mentioned on that thread too. The MTX plus is CMOS as is one MTX, the other I've reverted back to NMOS for testing. The cards I've been using are, the STEC128mb cards you sent, Kingston 4gb and Integral 2gb. No issues really with any of the...
by Martin A
28 Jun 2019 14:13
Forum: PROGRAMMING
Topic: Bootstrap and boot blocks
Replies: 79
Views: 983

Re: Bootstrap and boot blocks

@martin: I assume you can safely use the chained CTC channels because you've not got to worry about the comms card ? Is there any reason for not just switching to 16MHz at boot - is 8MHz because that's what works reliably or just an example ? Actually the 2nd channel comes from the tape interface, ...
by Martin A
28 Jun 2019 12:19
Forum: PROGRAMMING
Topic: Bootstrap and boot blocks
Replies: 79
Views: 983

Re: Bootstrap and boot blocks

The MTXplus has some very fancy clock controls designed by Tony Brewer. The CPU is booting at 4mhz, but can be switched up to 16mhz in 16 steps. http://primrosebank.net/computers/mtx/projects/mtxplus/firmware/mtxplus_fw_clocks.htm The same system keeps track of VDP writes and automatically inserts Z...