Search found 556 matches

by 1024MAK
Fri May 24, 2019 12:08 am
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 6554

Re: Asymmetric multiprocessing...

The hardware for an Tube “interface” does not even need a DPRAM. The hardware of the second processor does all the hard work. The Tube “interface” or port is just buffered address and data busses. Plus some control lines. Like this: Address lines A0 to A2 (A0 to A6 are present on the BBC B and Maste...
by 1024MAK
Wed May 22, 2019 2:13 pm
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 6554

Re: Asymmetric multiprocessing...

The NMOS and CMOS Z80 microprocessors always put a sixteen bit address out on the address bus. Including during I/O and DRAM refresh operations. The Zilog documentation always specifies the lower 8 bits (A0 to A7). For some operations, the Zilog documentation also specifies the higher 8 bits. How us...
by 1024MAK
Mon May 20, 2019 7:54 am
Forum: General QL Chat
Topic: Internet and the QL
Replies: 38
Views: 4388

Re: Internet and the QL

As browsing the Internet even using older PCs is now getting more and more painful, and as more and more emails contain photos, images and attachments (and most of the time, the user can’t select which emails get downloaded), I think the most useful reason for having Ethernet on a QL would be the sa...
by 1024MAK
Sun May 19, 2019 4:50 am
Forum: Hardware
Topic: Asymmetric multiprocessing...
Replies: 71
Views: 6554

Re: Asymmetric multiprocessing...

Maybe a 6809 (Hitachi 6309) so that OS-9 or UniFlex can be run... Incidentally was/is OS-9/68K available for the QL? And what about the other way round with a more modern fast processor (maybe in FPGA) being used as the main processor with the QL being used as the I/O processor... Maybe even a super...
by 1024MAK
Sat May 11, 2019 3:39 pm
Forum: Hardware
Topic: PC mouse to QL conversion project
Replies: 27
Views: 2959

Re: PC mouse to QL conversion project

The RS232 standards are mostly concerned with connecting Data Terminal Equipment (teletypewriters and later computers and other equipment) and Data Communications Equipment (MODEMs). Indeed, a 25 pin D connector cable should be straight through in this application. The only reason for the cable bein...
by 1024MAK
Wed Mar 27, 2019 12:26 am
Forum: General QL Chat
Topic: Why the QL ?
Replies: 42
Views: 4673

Re: Why the QL ?

Why, because I’m nuts...! Timeline... 1982-1983 watched various TV programmes that featured ‘home computers’. Wanted one :mrgreen: 1983 Christmas - Got a ZX Spectrum 48k :D 1984-1989 ish - upgraded the Spectrum and continued to use it. Was interested in the QL, but the magazine reviews were not good...
by 1024MAK
Fri Mar 01, 2019 11:02 pm
Forum: Hardware
Topic: QL test points...
Replies: 19
Views: 2111

Re: QL test points...

A secondary diagnostic microcontroller.
by 1024MAK
Sat Jan 12, 2019 1:50 pm
Forum: Hardware
Topic: LM7805 3A
Replies: 7
Views: 1393

Re: LM7805 3A

2) Replace the regulator with a switching buck regulator. This type of a regulator acts similarly to what would be a DC transformer (for reference, a real transformer can only operate on AC). The efficiency is very high so very little excess heat is generated, to the point where a heatsink is not n...
by 1024MAK
Sun Jul 29, 2018 4:17 pm
Forum: Hardware
Topic: Video issue over rf. Changes with reset
Replies: 7
Views: 1384

Re: Video issue over rf. Changes with reset

The RF output comes from the modulator. All the modulator does is to put the composite video signal onto a high frequency carrier. The main problem with the modulators and hence the RF output, is that these are analogue devices which use a capacitor-inductor to form the high frequency oscillator, so...
by 1024MAK
Sun Jul 01, 2018 10:54 am
Forum: Software & Programming
Topic: Unique original firmware from the Sinclair Archives
Replies: 10
Views: 1960

Re: Unique original firmware from the Sinclair Archives

While on the subject of the early QL machines that were supplied with a dongle, does anyone have any good quality photos of the the populated board that they used? Or know of web site(s) that have such photos?

Mark