Search found 7 matches

by tynemouthsoftware
Mon Jan 20, 2020 12:22 pm
Forum: Development
Topic: ZX81 Clone Tynemouth Minstrel 3
Replies: 22
Views: 5540

Re: ZX81 Clone Tynemouth Minstrel 3

Looks interesting. A couple of questions. What extra software can you now run with the 56K RAM that couldn't run before, and are there any programs which did run with 16/32K but will not work with the extra RAM? I have not found much software which needs more that the standard 16K, so trying to judg...
by tynemouthsoftware
Thu Jan 09, 2020 1:05 pm
Forum: Development
Topic: ZX81 Clone Tynemouth Minstrel 3
Replies: 22
Views: 5540

Re: ZX81 Clone Tynemouth Minstrel 3

The Minstrel 2 and Minstrel 3 are both ZX81 shaped, so will not fit in a ZX80 case. They are designed to be used in a ZX81 case or standalone.

There are some ZX80 clones that are the right shape and size for a ZX80 case, but the Minstrel boards are not.
by tynemouthsoftware
Sat Jan 04, 2020 8:25 pm
Forum: Development
Topic: How to enable ZX-Key external keyboard with Minstrel 3 board
Replies: 8
Views: 1672

Re: How to enable ZX-Key external keyboard with Minstrel 3 board

One option I suggested when this was first raised was to swap out the 257s that are used for the keyboard read with 74LS257s. The LS is good at pulling down, but has a weak pull up. If the ZX-Key interface is driving low strongly with it's HCT245, that may be enough to register? The main thing those...
by tynemouthsoftware
Thu Jan 02, 2020 11:20 am
Forum: Development
Topic: ZX81 Clone Tynemouth Minstrel 3
Replies: 22
Views: 5540

Re: ZX81 Clone Tynemouth Minstrel 3

Thanks for posting the findings, interesting to see how that worked out. I had tried to remove as many of the analogue bits of the design like those RC filters, but had to leave those in as I couldn't get the timing right using the synchronous 74166 rather than the giving a short pulse to the non-sy...
by tynemouthsoftware
Thu Jan 02, 2020 11:00 am
Forum: Hardware
Topic: Which ROM for Minstrel 3?
Replies: 21
Views: 1216

Re: Which ROM for Minstrel 3?

Thank you, I'm pleased you appreciate the work that went into the layout of the Minstrel boards. The ROM can be the standard ZX81 ROM. I suggest using all the jumpers high to allow compatibility with the most types of EPROM. The pins that are used for the higher address lines on a 27C512 are used fo...
by tynemouthsoftware
Fri May 04, 2018 11:11 pm
Forum: Hardware
Topic: zx spectrum in zx81 case
Replies: 63
Views: 18661

Re: zx spectrum in zx81 case

I also had an issue with one of the clocks, but in my case it was the 4.43MHz clock used for the colour timing. I used an 74HCU04 (the same as used on the +2 if I remember correctly). http://blog.tynemouthsoftware.co.uk/2018/02/keyboard-options-for-zx-max-48.html If the 14Mhz isn't running, that mig...
by tynemouthsoftware
Sat Feb 03, 2018 3:05 pm
Forum: Hardware
Topic: zx spectrum in zx81 case
Replies: 63
Views: 18661

Re: zx spectrum in zx81 case

Thanks to McKlaud for sending me a PCB and a CPLD, I've built up a ZX Max 48 and looked at some keyboard options. The keyboard overlay was an interesting challenge, and I think it has come out very nicely. https://3.bp.blogspot.com/-Gx_aFVEKMEs/WnWuoBrN1kI/AAAAAAAAN40/ts9HfC2_Ob0euqPk5IEEd3waumqt7hO...