Search found 592 matches
- Thu Apr 02, 2020 12:59 pm
- Forum: Hardware
- Topic: Confusion over Aurora Mouse port numbering
- Replies: 5
- Views: 1817
Re: Confusion over Aurora Mouse port numbering
Keep in mind that conventional D-connectors existed before the idea was thought up of making IDC versions that could connect to IDC cable. Hence the numbering gets a bit confusing. Atari, Amiga, Acorn and some early PC mice are ‘bus’ mice. Two TTL digital lines are encoded with square waves for each...
- Tue Mar 31, 2020 10:33 am
- Forum: Hardware
- Topic: QL Add-on ROM
- Replies: 34
- Views: 10137
Re: QL Add-on ROM
I strongly recommend you do use a resistor to pull up undriven address line inputs. For CMOS chips, a value of between 4.7kΩ and 10kΩ is suitable. If an address line for a CMOS SRAM is allowed to float, it will pick up interface and static charge from other conductors or conductive bodies/objects. A...
- Tue Mar 31, 2020 9:34 am
- Forum: Hardware
- Topic: QL Add-on ROM
- Replies: 34
- Views: 10137
Re: QL Add-on ROM
I would prefer a wizard, they tend to be more reliable and trustworthyDave wrote:You could have a physical witch to connect /WR. If you tie it to 5V it can’t be written. A mechanical pull-up.
Mark
- Sun Mar 29, 2020 3:56 pm
- Forum: General QL Chat
- Topic: Help with Composite out
- Replies: 57
- Views: 27211
Re: Help with Composite out
Some questions: Am I reading that correctly with regard to SCART going into the two different modes? Some TVs (not many these days) have a user control to select which input system to use on the first (if more than one) or only SCART input. Most automatically switch input mode depending on the inpu...
- Sun Mar 29, 2020 3:23 pm
- Forum: General QL Chat
- Topic: Help with Composite out
- Replies: 57
- Views: 27211
Re: Help with Composite out
SCART (under a different name) is a product of the French. They passed a law requiring this type of connector to be fitted to all consumer TV/video equipment. It then became popular across Europe. But it has never been popular in the USA. As far as I am aware, nearly all TVs sold in the USA do not h...
- Mon Jan 27, 2020 2:03 pm
- Forum: The Off-Topic Section
- Topic: QL vs BBC vs Amstrad 464
- Replies: 9
- Views: 5188
Re: QL vs BBC vs Amstrad 464
The 6502 CPU used in the BBC Micro only uses the data-bus when the CPU clock is high. Hence if you isolate the address and data lines, the video system can use the time when the CPU clock is low to get screen data from the main RAM. Hence no slowdown. Note that this does not apply if you want your 6...
- Sat Jan 04, 2020 11:38 am
- Forum: For Sale
- Topic: Anyone interested in a brand new Sinclair ZX80 case?
- Replies: 5
- Views: 3633
Re: Anyone interested in a brand new Sinclair ZX80 case?
The original cases were vacuum formed. This is where a flat sheet of plastic is heated, then a vacuum pulls the plastic over a mould to form the shape. Any cut-outs that are required then need to be machined out. Injection moulded cases are described by Rick Dickinson in some detail on this page . B...
- Wed Jan 01, 2020 11:12 am
- Forum: For Sale
- Topic: Anyone interested in a brand new Sinclair ZX80 case?
- Replies: 5
- Views: 3633
Anyone interested in a brand new Sinclair ZX80 case?
A member of the Sinclair ZX World forum is trying to get a run of brand new Sinclair ZX80 cases manufactured. He says this: I've been working hard recently in getting together different manufacturers in order to produce an EXACT copy of the Sinclair ZX80 case, either the original, or the later injec...
- Fri Dec 27, 2019 5:24 pm
- Forum: Wanted
- Topic: Schon keyboard
- Replies: 13
- Views: 11250
Re: Schon keyboard
These keyboards may have some problems, but then, there are not many keyboards that are over 30 years old that don’t have at least some problems...
Mine (see here) still works okay. Although I don’t use this machine as my regular QL.
Mark
Mine (see here) still works okay. Although I don’t use this machine as my regular QL.
Mark
- Mon Dec 23, 2019 10:29 pm
- Forum: Hardware
- Topic: Keyboard Interface problem
- Replies: 44
- Views: 14016
Re: Keyboard Interface problem
Some early AT keyboards had a switch to select XT mode. Of course that won’t help if all you have are PS/2 keyboards... If you search the ‘net you will find that there are three keyboard protocols for the five pin DIN system. It should also be possible to use a microcontroller to carry out a convers...