Search found 237 matches

by Bill B
02 Feb 2020 20:07
Forum: OFF TOPIC
Topic: Another Home-Brew - Z180
Replies: 53
Views: 8130

Re: Another Home-Brew - Z180

Dave, That issue had occurred to me, and is a possibility. I am not sure there was an error message, other than "Failed", when attempting to program. When I did the JTAG test, I got the "No device found" message. I don't remember exact messages, and don't have the system in front of me at the moment.
by Bill B
02 Feb 2020 15:19
Forum: OFF TOPIC
Topic: Another Home-Brew - Z180
Replies: 53
Views: 8130

Re: Another Home-Brew - Z180

Martin,

Thanks for the suggestion. It may be that, but I don't think so. The lead seems to be good quality and a good fit. Also there is activity on the programmer LED when attempting to program.

Experimentation is required.
by Bill B
02 Feb 2020 13:38
Forum: OFF TOPIC
Topic: Another Home-Brew - Z180
Replies: 53
Views: 8130

Re: Another Home-Brew - Z180

I have surveyed the PCB with a multimeter. I found a few shorts, that I was able to correct. Once I was happy with the board, I installed power leads and the CPLD. Connected power supply and programmer. I am using this programmer. Attempted to program the device: Failed. JTAG error. No device detect...
by Bill B
01 Feb 2020 14:13
Forum: OFF TOPIC
Topic: PCBs for Spectrum Clones
Replies: 17
Views: 1735

Re: PCBs for Spectrum Clones

And since it is the RGB to NTSC/PAL Encoder, do you need it?

If you have a monitor with RGB input, then you could just leave it out.
by Bill B
26 Jan 2020 19:00
Forum: OFF TOPIC
Topic: Another Home-Brew - Z180
Replies: 53
Views: 8130

Re: Another Home-Brew - Z180

Martin, On less dense boards I have done that. However you have to bend the wire over to stop it just falling through the hole and the bent over bit adds to the problem of bridging adjacent tracks. That is what failed my 31st Dec attempt. I have been trying to think of a way of evenly spreading the ...
by Bill B
26 Jan 2020 14:00
Forum: OFF TOPIC
Topic: Another Home-Brew - Z180
Replies: 53
Views: 8130

Re: Another Home-Brew - Z180

Progress at last 20200126_103449.jpg Lots of steps involved: The layout was revised to ensure that all vias were at least 0.1 inch apart. I created a number of footprints consisting of ovals of different orientations on the upper and lower layer, such as Via_Image.png and placed them over the vias, ...
by Bill B
25 Jan 2020 22:42
Forum: GENERAL DISCUSSIONS
Topic: Using more than 64k on the MTX
Replies: 7
Views: 1099

Re: Using more than 64k on the MTX

I have never been sure whether the RAM disk has to be F, or whether it could be G, H, or I.

But to search the drive type table for type 51 would probably work, thanks.
by Bill B
25 Jan 2020 15:42
Forum: GENERAL DISCUSSIONS
Topic: Using more than 64k on the MTX
Replies: 7
Views: 1099

Re: Using more than 64k on the MTX

Martin, I was more thinking of detecting a RAM disk from CP/M. Specifically, enabling M576ZVM to warn the user that their RAM disk is about to be clobbered :) I suspect that part of the reason that there is little software making use of more than 64K is that there were very few machines back in the ...
by Bill B
25 Jan 2020 12:46
Forum: OFF TOPIC
Topic: PCBs for Spectrum Clones
Replies: 17
Views: 1735

PCBs for Spectrum Clones

Probably prompted by my struggles with making my own PCBs, Lez as gifted me with three professionally made PCBs: ZX Max 48 Superfo Harlequin 128 Superfo Harlequin +3 Since I am stubborn and determined to build my own design, I thought I would pass at least a couple of these boards on to others. Note...
by Bill B
24 Jan 2020 21:34
Forum: GENERAL DISCUSSIONS
Topic: Using more than 64k on the MTX
Replies: 7
Views: 1099

Re: Using more than 64k on the MTX

I suspect that with MTX Basic, the main use of more than 64K would be for large data arrays rather than just for code. If I remember correctly, simple variables are stored in common RAM above 48K and are limited to less than 16K. Arrays (and strings), however, are stored immediately after the Basic ...