External QL-SD

[Derek_Stewart]

Hi Peter,

The Atapi CDRom device driver is not complete, although I used to setup a Q60 with a CDROM drive as a Primary Slave on the IDE bus. QCDEZE does read the CD disks, but is not a device driver. Duncan Nethercut, the author of QCDEZE, bought a Q60, I did ask him if he could write a device driver, but I never followed it up.

I used custom CDROM disk with a QXL.WIN image file written onto the CDROM disk and use Wolfgang Lenez's QXLWIN programme to read the CDROM disk. This was utilised to customise the Q60 software package.

I always wanted to write the device driver for native CD Aptapi file access, but never got around to it.

I suppose SMSQ/E could be altered to fit onto a Q60 eprom and slimmed down to run on a standard QL with a ram expansion. I would think 256Kb expansion would be the bare minimum for SMSQ/E, considering the Extended environment is integrated.

SMSQ/E on Gold Card, SUper GOld Card, Q60/Q40 is soft loaded, I am not sure this would work on a standard QL, as there is no shadow ram. So maybe a eprom is the way forward here, I will look into this and get back to you.

[Peter]

It may also be possible to override the system ROMS in the $00000-$10000 area, and replace them with ROM mapped from the flash.

Does asserting DSMCL allow you to do this ?

When DSMCL is pulled high, the internal decoding is disabled. So yes, this signal can be used for this purpose. I'd just not call pulling the line high "asserting", since DSMCL is a low-active signal, reflecting the DSL signal from the CPU, if not overridden.

[Paul]

Sorry Guys, but I really can't see that any of the posts have anything to with External QL-SD
Even the extension bus QL-SD is internal
I also designed an extension bus version of QL-SD with RAM but decided against it as it will find less buyers because people already have trump cards etc. they would like to continue to use and, even more important, I still have a large Batch of QLROMEXT PCBs I can use in the external version for the ROMPORT. This Idea came because I only have another 15 QL-SD internal PCBs and after having sold about 50 internal QL-SD with QLROMEXT, producing another batch of internal QL-SD PCBs seems to be kind of a risk as selling them has dramatically slowed down.
The ROMPORT version does adress a different user type (not opening the QL at all) and there might be a market for it, provided there is a RAM expansion avaialble.
The only thing I regret is: there is still no version of QL-SD that is suitable for self soldering as a kit.
The ZX81 hardware scene is much bigger because the extensions are suitable for wire wrapping or being availabe as a kit. This adresses another market of soldering fans that buy a ZX81 to drive their extensions

[prime]

The only thing I regret is: there is still no version of QL-SD that is suitable for self soldering as a kit.
The ZX81 hardware scene is much bigger because the extensions are suitable for wire wrapping or being availabe as a kit. This adresses another market of soldering fans that buy a ZX81 to drive their extensions

Well I have managed to get the QL-SD Verilog code running on a Xilinx XC9572XL PLCC-44 CPLD, that is hand solderable, put that on a card with a DIP ROM and you should be good to go.

Actually one of the reasons that the FloppySD with RAM is so big is that it is all DIP or PLCC, as I thought I might be home building the initial prototype boards, and that's much easier with DIP/PLCC, especially as it means you can socket stuff and re-use it if said prototype doesn't work.

Cheers.

Phill.

[vanpeebles]

My soldering skills are awful so I'm glad someone else makes them I once modded a sega saturn to be no region

[Peter]

Sorry Guys, but I really can't see that any of the posts have anything to with External QL-SD

If you read exactly, you find points where I was on-topic regarding your interface. E.g.the production issue and the easier EPROM change for OS development.

But despite your external QL-SD, I find other external interfaces which contain QL-SD also worth discussing here. I almost did a thread change, but that tends to disrupt the course of conversation.

Even the extension bus QL-SD is internal

Not if you look how the I/O space is defined in the classic QL literature.

The only thing I regret is: there is still no version of QL-SD that is suitable for self soldering as a kit.

This is definitely my fault. Internal meant small. If it was not for dual use of QLROMEXT boards, an external interface would be the oportunity to use a PLD than goes into a wired PLCC socket.

Preferably an old slow 5V PLD, so there also is a chance to circumvent the signal issues with (S)GC.

The ZX81 hardware scene is much bigger because the extensions are suitable for wire wrapping or being availabe as a kit.

Couldn't it be 1.5 million ZX81 sold, versus 150000 QL?

[Peter]

The Atapi CDRom device driver is not complete, although I used to setup a Q60 with a CDROM drive as a Primary Slave on the IDE bus. QCDEZE does read the CD disks, but is not a device driver.

Fully agreed. I just wanted to point out there is native CDROM access software at all. That may not be obvious for many forum readers.

SMSQ/E on Gold Card, SUper GOld Card, Q60/Q40 is soft loaded, I am not sure this would work on a standard QL, as there is no shadow ram.

It is simply impossible, if you do not at least add an EPROM adaptor, so you can change the OS (or loader) to allow some kind of exception redirection. The external QL-SD provides that EPROM adaptor. (Hurray, back on topic.)