PCW-IO

[Habi]

Greetings.

Having several PCW boards around ("thanks" to the PCWWiki Project: http://pcwwiki.amstrad.es/doku.php?id=en:hardware:placas), I tried to make a video and keyboard adapter for them.

Things got out of hand, so I ended adding a programmable joystick, mouse (KeyMouse) support and a PAL / NTSC switch. 

Regards.

[||C|-|E||]

This is supercool, honestly, and a great way to give a second life to many spare motherboards 

[robcfg]

Indeed!


A super fine job as usual 

[MaV]

Beautiful work!

[Habi]

Thanks! That was the idea, to put again into service those bare PCBs, or broken PCWs. 

The design is modular: you can have keyboard but no video, or any combination. Also, there are 4 unused pins in the microcontroller that can be used for several things like: hardware reset via keyboard, substitute frontal gotek buttons with numeric + and -, ...

Anyway, I'll upload everything to PcwWiki (like the clones of Dk'sound and diagnostics board) when I have a final version.

Regards.

[TFM]

Sorry for getting a bit off-topic... it there a ROM expansion for the PCW?

[robcfg]

Habi managed to use the diagnostics board with a game rom instead, but nothing like a CPC rombox.

[TFM]

Habi managed to use the diagnostics board with a game rom instead, but nothing like a CPC rombox.

That's what's really missing on the PcW. Imagine to boot from ROM (Flash of curse) and even have some files installed in ROM (like the CP/M Plus on CPC with its applications in ROM).

Sadly the PcW Wiki doesn't tell much about the test board (f.e. how much ROM is there?)

At least there are decent RAM expansions for the PcW. 

[robcfg]

I've just asked Habi and the rom size is 32KB.


He compressed Goody from Opera Soft and booted it from the board.

[Habi]

There is no need for a ROMBox, because that's not how the PCW works...

But there is at least a Flash drive for the PCW: the Cirtech one. 

All said, it's quite easy to add memory to the PCW, being it RAM, ROM or mapped I/O. Up to 2MB using standard method, and as much as you want otherwise.

Regards.

[TFM]

There is no need for a ROMBox, because that's not how the PCW works...

Excuse me, can I please use my computer in the way I want? Thank you!    And therefore there *IS* a need for a Flash-ROM expansion at least for me and few others who are interested in boosting this nice machine a bit. 

[Habi]

Excuse me, can I please use my computer in the way I want? Thank you!    And therefore there *IS* a need for a Flash-ROM expansion at least for me and few others who are interested in boosting this nice machine a bit. 

Ha, ha! You're right, sir! 

I've seen ROMs in devices that can boot from another media (like the Cirtech GEM, or the Test PCB), and it's quite easy to override the initial default boot.

Personally I don't see the need for a ROMBox, and also all prexisting software should be patched (making it incompatible). But I'll be happy to see new hardware (or software) for the PCW.

Regards.

[TFM]

Thank you Sir!

Well, just thinking about some kind of ROM disc, in which you can have all your favorite tools/apps/games. To patch CP/M could be even more easy compared to CPC (according to SyX, he told that the Joyce CP/M has this nice 'driver feature'). However I have to catch up learning more about the PcW CP/M specialties. 

Of course you're right: A quick mass storage kind of eliminates the need of a lot of other things. 

[Bryce]

From a speed and comfort perspective, a ROMBox is always a cool expansion to have. However, they become a bit non-practical when the computer has multiple times more RAM than a ROM can hold. With the CPC it was already borderline: 64K/128K RAM, but each ROM has only 16K. Still there were 16K games, but when you then move up to computers with 512K or more the ROM makes much less sense. Yes, you could make a ROMBoard with 16x 512K per ROM, but at that stage the price just can't be justified.

Bryce.

[TFM]

From a speed and comfort perspective, a ROMBox is always a cool expansion to have. However, they become a bit non-practical when the computer has multiple times more RAM than a ROM can hold. With the CPC it was already borderline: 64K/128K RAM, but each ROM has only 16K. Still there were 16K games, but when you then move up to computers with 512K or more the ROM makes much less sense. Yes, you could make a ROMBoard with 16x 512K per ROM, but at that stage the price just can't be justified.
Bryce.

The price? Well, looking at the price of the X-MEM for 1 MB that price is just fine. But let's please not discuss pricing here. However what I don't get is the point you try to make about RAM replaces ROM??? Expansion RAM as expansion ROM is handled in 16 KB blocks (Joyce and CPC), so why not having more ROM - especially when having RAM. Don'f forget a disc for the PcW can only load 0.7 MB at once. And as nice as all the hard-disc solutions for the PcW are, in reality nobody can buy them, because they are nowhere to get.


As pointed out before, it's not a problem to use ROM as something like a super fast storage medium.    And the more RAM you have the more you need a "source" to fill it up. 

[Bryce]

You've slightly mis-understood what I was trying to say and then agreed with it to some extent.

My point is that ROM is usually used to quickly transfer a program to RAM. Most ROMBoards could hold 16x (or 32x) 16K programs, but  the CPC could handle 64K, so the programs weren't using the full potential of the CPC (unless they used multiple ROMs). With the PCW the gap widens. The computer can handle much larger programs than are commercially viable for a ROMBoard. To make it useful the ROMBoard would need to have at least 16x 512K, which is a rather complicated and large ROMBoard.

Bryce.

[Habi]

However, they become a bit non-practical when the computer has multiple times more RAM than a ROM can hold.

Indeed, but not only that.

The CPC series have a standard way to expand it with ROMs, both hardware (port $DFxx) and software (firmware which recognises them and expand the commands available to the user). The PCW doesn't have anything like that, and in fact doesn't even have a boot ROM.

To patch CP/M could be even more easy compared to CPC (according to SyX, he told that the Joyce CP/M has this nice 'driver feature').

Yes, Locomotive made its BIOS in such a way it loads FID/FIB files at boot (and they did the same thing on the CP/M for Spectrum +3). I'm surprised they didn't do the same on the CP/M+ for CPC.

Don'f forget a disc for the PcW can only load 0.7 MB at once.

Agreed, a massive storage medium is something really needed.

For the record, I started a CompactFlash device (with hardware / software floppy emulation), then discard it in favour of a USB solution, then discard it again in favour of a Wi-Fi module (the Cloud is the future!), then discard it altogether as I have very little time.

[Bryce]

Yes, I left out the fact that the PCW doesn't have the infrastructure for ROMs as other computers do.

However, a decent low cost IDE interface should be pretty simple to put together for the PCW. Where's the problem?

Bryce.

[Habi]

Yes, IDE is simple and, using a CF in 8-bit mode, also cheap (no need for a 16-bit bus).

I had made, in fact, a small boot ROM with some functionality, including reading a FAT partition.

But I think IDE /CF is a bit dated, they will be difficult to find in the near future. A USB or Wi-Fi solution will probably be better now and in the future.

[Bryce]

CF cards will be around for quite a while yet, they are used in many industrial applications, and even if they disappeared, it would be simple to convert your device to SD.

Bryce.

[Habi]

Hmmm... maybe you're right. Just a simple IDE interface without emulation of floppy, snapshot write support, etc.

A pair or utilities to partition and format it (up to 512 MB if I recall correctly), and it's done.

I'll think about it.

[Bryce]

Did I hear a soldering iron being turned on just there?

Bryce.

[TFM]

@Habi : Well spoken Sir, guess you're just right. I may have to learn a lot about that topic.