Hot answers tagged

16 votes
Accepted

How big is the screen of the Amstrad CPC 464?

The CPC 464 was sold with either a green-screen monitor, the GT64, or a colour monitor, the CTM460. The former has a 12” tube (11.4” visible), the latter a 14” tube (13.5” visible). The screen wasn’t ...
user avatar
  • 96.6k
14 votes
Accepted

Did early versions of DR-DOS preserve more registers than MS-DOS?

TL;DR: MS_DOS preserved all registers, thus DR-DOS can not have preserved more. It sounds much like memory blurred by time. Was this true, Seems hard to believe. Hard to answer as well, as no ...
user avatar
  • 173k
9 votes

How long are interrupt requests remembered on the Amstrad CPC?

but I can't find any explicit documentation. The documentation for the Z80 behaviour is in its manual. For the way the CPC hardware handles it, you may need to see these circuits. It may, for example ...
user avatar
  • 173k
9 votes
Accepted

How long are interrupt requests remembered on the Amstrad CPC?

According to this CPCTech entry: In the CPC the Gate Array generates maskable interrupts, to do this it uses the HSYNC and VSYNC signals from the CRTC, a 6-bit internal counter and monitors the ...
user avatar
  • 32.5k
7 votes

Did early versions of DR-DOS preserve more registers than MS-DOS?

For comparison with @Raffzahn's description above, here's how the INT 21h entry point works in DOS Plus. In the INT 21h handler, the function number is compared with 2Fh. Functions up to 2Fh are ...
user avatar
  • 5,882
7 votes

Are all 64k x 4-bit ICs interchangeable for Amstrad-era ZX Spectrum 128k +2/+3?

Yes. Speed must be 150ns or faster, technology should be NMOS (CMOS produces too sharp edges that may cause ringing, due to non equalized traces in the PCB, so they may or may not work) and must ...
user avatar
7 votes
Accepted

What did "double track" mean in relation to floppy disks?

It’s just nomenclature for 40-track (‘single’) versus 80-track (‘double’) drives. It’s not 3”-specific, e.g. here is a reference using the same terminology for 5.25” drives; 3” drives don’t do ...
user avatar
  • 32.5k
6 votes
Accepted

Amstrad CPC 6128 - Bench Power Supply Connection Setup

CPC Machines were powered by 5v DC from monitor to the 2.1mm socket on the machine. Any power supply that meets these requirements with the correct polarity should work. The plug has one outer and one ...
user avatar
6 votes
Accepted

Trying to create a filesystem ROM for Amstrad CPC but tape is still waiting

As I was expecting, it was an error in my code :) pelrun was very kind and found the bug (see my question on CPCWiki's forum) so props to him. I'll try to explain the issue: Notice I'm hooking into ...
user avatar
  • 251
5 votes
Accepted

Who produced all-in-one / wedge style IBM compatibles?

Three jump direct to mind: Schneider Euro-PC and Euro-PC II Amstrad PPC Vendex Headstart Explorer Laser Compact XT by VTech (thanks mnem) Not to mention the WEB-IT, a 486 based as an all in one unit,...
user avatar
  • 173k
5 votes

How long are interrupt requests remembered on the Amstrad CPC?

As far as I know, no /INT is remembered as it is purely level-triggered, as @Raffzahn noted. So losing interrupts in your conditions is just expected. Same design is in ZX Spectrum, with probably a ...
user avatar
  • 9,326
4 votes
Accepted

How can I format a higher capacity 3 inch disc on a regular CPC6128?

Nemesis' Bonzo Doo Dah and Richard Monteiro's FastForm/BigK in Amstrad Action Issue 16 gave somewhere between 203 – 206 K per side, leaving one or two standard tracks for a small boot stub to load up ...
user avatar
  • 17.2k
4 votes

How to determine where in RAM the current Basic program resides on Amstrad microcomputers?

The Locomotive BASIC is a bit of an oddity as the start of the BASIC area is hardcoded to 0170h (for the CPCs) and no indirection via a pointer is given. Then again, location AE26h (*1) is checked ...
user avatar
  • 173k
4 votes
Accepted

How to determine where in RAM the current Basic program resides on Amstrad microcomputers?

With a bit of googling: http://www.cpcwiki.eu/forum/amstrad-cpc-hardware/memory-map/ (information is not very widespread, I could not find any confirmation somewhere else) Basic starts at &170 ...
user avatar
4 votes

Which addresses does the Motorola 6845 CRTC output during retrace?

Short answer from memory: At the beginning of a frame the address is set to zero The address is incremented over a line for R0 (total chars aka horizontal timing) character access cycles. Only R1 (...
user avatar
  • 173k
3 votes

How to determine where in RAM the current Basic program resides on Amstrad microcomputers?

In Locomotive Basic the program is stored after the end of the ROM lower reserved area. There is a pointer to that, AE64hex on the 6128, AE81hex in the 464, according to the firmware guide. It's value ...
user avatar
3 votes

How to determine where in RAM the current Basic program resides on Amstrad microcomputers?

Under CP/M, the program start address in Mallard BASIC differs by version. I'm not aware of any fixed location that can be interrogated to find it; however, it may be possible to determine it by ...
user avatar
  • 5,882
3 votes

Is there a "most correct" name for the disk format / filesystem used by Amstrads and Spectrum +3's?

I don't remember them having a “name”. Disk interchangeability was less of a thing than it became between 16-bit computers. Amstrads were very much not interchangeable, since they had the Hitachi 3" ...
user avatar
  • 17.2k
3 votes

Who produced all-in-one / wedge style IBM compatibles?

There was the Schneider Euro PC. Schneider had been selling Amstrad computers (the CPC line, the PC 1512/1640, and the Joyce) in Germany. The Euro PC in 1989 was their first attempt at an own design, ...
user avatar
  • 7,854
3 votes

First time using an Amstrad CPC 6128 Disc Drive

. how do I get in todays infrastructure a *.dsk program on a 3" disk, when the disk drive itself is currently being refurbished. I sense a basic plot hole: Even if you would get it on a disk (*1)...
user avatar
  • 173k
2 votes

Amstrad CPC 6128 - Key cap spring missing

In the worst of the cases, in which you had really lost it you could try the following options which do not require buying specialized springs: Scavenge springs from broken/unusable equipment. Pens ...
user avatar
2 votes

First time using an Amstrad CPC 6128 Disc Drive

I have a "Gotek USB floppy emulator" in my CPC6128 (with ParaDOS and the 3.5" FDD interface mod). It has the same connector as the floppy drive and the USB connector for the USB Flash ...
user avatar
  • 5,162
2 votes
Accepted

First time using an Amstrad CPC 6128 Disc Drive

The easiest (and my recommended) way: Get an M4 board. This expansion allows to push .dsk images to an SD card connected to your CPC via a simple Web browser and Wi-Fi interface. From there, you could ...
user avatar
  • 28.4k
2 votes

Who produced all-in-one / wedge style IBM compatibles?

I had (though have since sold) a Key-Comp 386 similar to the one pictured at atariage.com. It had two ISA slots (for video and network cards) at the left-hand end of the case, and built-in parallel ...
user avatar
  • 5,882
1 vote

How can I format a higher capacity 3 inch disc on a regular CPC6128?

This is not yet a complete and verified answer, because I haven't tested it on real hardware. There is a utility by CNGSoft called '2H' (written in 2013) which claims a capacity of 208K, using 41 ...
user avatar
1 vote

Which addresses does the Motorola 6845 CRTC output during retrace?

The horizontal counter increments continuously with the CRTC clock, and the vertical counter (divided into a pixel row counter and a text line counter) increments continuously with the horizontal sync ...
user avatar
  • 16.1k
1 vote

Is there a "most correct" name for the disk format / filesystem used by Amstrads and Spectrum +3's?

The Amstrad CPC manual (chapter 7 part 12) listed three "disk formats" supported by AMSDOS, which it named "System", "Data only" and "IBM" (CP/M 2.2 only). All three of these formats had: 40 tracks ...
user avatar
  • 111
1 vote
Accepted

Are there open source Java libraries for reading DSK and EDSK disk image files as used by Amstrad and Spectrum +3 emulators?

It seems there is. There is an open source C library by John Elliot for working with a selection of disks and disk image formats called LibDsk, active as of August 2019. Among the supported formats ...
user avatar
  • 4,380

Only top scored, non community-wiki answers of a minimum length are eligible