Search found 229 matches

by McKlaud
Sun Dec 23, 2018 1:42 am
Forum: Sinclair Misc
Topic: Jupiter ACE (again)
Replies: 68
Views: 7672

Re: Jupiter ACE (again)

New toy arrived just before Xmas holidays. This time a simple AY chip interface with the 96K RAM module on a single board. AY chip uses the same ports (65533 & 49149) like in ZX Spectrum 128K. Anyway I am not a musician and can do simple shot sounds only but I am happy that it works.
by McKlaud
Wed Dec 19, 2018 10:38 am
Forum: Hardware
Topic: Issue 4B Spectrum with dot crawl in black and white
Replies: 13
Views: 845

Re: Issue 4B Spectrum with dot crawl in black and white

Any ceramic caps (single or multilayer) are good for this application. Don’t use tantal or electrolytic ones.
by McKlaud
Wed Dec 19, 2018 9:25 am
Forum: Hardware
Topic: Issue 4B Spectrum with dot crawl in black and white
Replies: 13
Views: 845

Re: Issue 4B Spectrum with dot crawl in black and white

220nF would be sufficient. This is not an issue with the capcistance only. In this application the main factor is ability to fast charging and discharging of these caps. So, the ESR would play the main role.
by McKlaud
Mon Dec 17, 2018 8:46 am
Forum: Sinclair Misc
Topic: Jupiter ACE (again)
Replies: 68
Views: 7672

Re: Jupiter ACE (again)

Jupiter ACE is not popular like ZX81. Please bear in mind that there was sold no more 10,000 units of Jupiter ACE in 80-ties. A few more replica PCBs in recent years do not make any difference. I would not be surprised if SirMorris said 'no'. Regarding the memory map, the partial address decoding of...
by McKlaud
Sat Dec 15, 2018 12:07 pm
Forum: Sinclair Misc
Topic: Jupiter ACE (again)
Replies: 68
Views: 7672

Re: Jupiter ACE (again)

Jupiter ACE memory map can be found there: http://k1.spdns.de/Vintage/Sinclair/80/ ... memory.txt

Please note that the 8K ROM is full. You can use larger EPROM chip but the address deciding is simplified and you will not gain much. The new address decoder is needed.
by McKlaud
Sat Dec 15, 2018 12:34 am
Forum: Sinclair Misc
Topic: Jupiter ACE (again)
Replies: 68
Views: 7672

Re: Jupiter ACE (again)

dessony : have a look into the Jupiter's memory map. It looks like a Swiss cheese :lol: due to a partial address decoding. Any user memory extension can sit between 0x4000h and 0xFFFF addresses. So, the easiest way to extend the user memory from 1K to 17K (+16K) is employing any 16K RAMpack for ZX8...
by McKlaud
Fri Dec 14, 2018 11:09 pm
Forum: Sinclair Misc
Topic: Jupiter ACE (again)
Replies: 68
Views: 7672

Re: Jupiter ACE (again)

I've been thinking about re-designing the PCB completely and make Jupiter in the ZX Speccy format, using newer components like 6116 SRAM chips instead of 2114, but this is a long shot.
by McKlaud
Fri Dec 14, 2018 10:57 pm
Forum: Sinclair Misc
Topic: Jupiter ACE (again)
Replies: 68
Views: 7672

Re: Jupiter ACE (again)

So sorry, I would not publish Gerbers or source files for the main PCB on any public website. I am not going to order another batch of these boards in near future, because I am busy with a few bits and bobs for my Jupiter. I should publish on there detailed photos how I made the keyboard useful. I h...
by McKlaud
Thu Dec 13, 2018 3:52 pm
Forum: Welcome Area
Topic: Hello from Argentina
Replies: 5
Views: 564

Re: Hello from Argentina

Hi Alex,

Good you joined us.

Kind regards
by McKlaud
Mon Dec 10, 2018 6:13 pm
Forum: Sinclair Misc
Topic: Jupiter ACE (again)
Replies: 68
Views: 7672

Re: Jupiter ACE (again)

unxiax: I’ve got a few boards left and not planning for any new batch.