The Sinclair QL Forum

Pr0f wrote:It seems the 2 biggest wants would be:

Replacement / improvement for the ZX8301

Replacement / improvement for the IPC that offers USB or PS/2 Keyboard support, but maintains the internal keyboard functionality.

I doubt that modern external keyboards for the original QL mainboard are a big want.
The original mainboard is mainly kept for nostalgia, therefore used with the black box and it's original keyboard, or other historic keyboards.

Peter wrote:

Pr0f wrote:It seems the 2 biggest wants would be:

Replacement / improvement for the ZX8301

Replacement / improvement for the IPC that offers USB or PS/2 Keyboard support, but maintains the internal keyboard functionality.

I doubt that modern external keyboards for the original QL mainboard are a big want.
The original mainboard is mainly kept for nostalgia, therefore used with the black box and it's original keyboard, or other historic keyboards.

A good point Peter. Alhough I can forsee a time when the rubber mats or keyboard membrains are no longer available... Would be a pity to discard the old black slab just because it's keyboard died and was no longer repairable...

At least replacements for QL membrane or rubber mat could be reproduced. That has been done before, and if the retro-boom continues, the investments might be manageable.

What worries me much more is the ZX8301. I'm not even sure that a PCB-based replacement for this chip would be accepted widely enough to justify the massive amount of work. Collectors and nostalgist tend to prefer original looking components. But that's something Rich Mellor can judge better than me.

Peter wrote:What worries me much more is the ZX8301. I'm not even sure that a PCB-based replacement for this chip would be accepted widely enough...

But it is the most problematic for modern monitors and therefore the device most likely to be acceptable as replaceable even for purists?

Good to hear Rich still has plenty of ZX8302 (the only chip I have ever broken )

Though I'm very thankful that my Philips V7001 and CM8852 still are holding out

Pr0f wrote:Replacement / improvement for the IPC that offers USB or PS/2 Keyboard support, but maintains the internal keyboard functionality.

Couldn't one of the serial ports be used for a PS/2 external keyboard? It would only require a bit of software to act as a driver passing the keyboard input to the operating system so either keyboard could be used or even have one hand on each.

Ruptor wrote:

Pr0f wrote:Replacement / improvement for the IPC that offers USB or PS/2 Keyboard support, but maintains the internal keyboard functionality.

Couldn't one of the serial ports be used for a PS/2 external keyboard? It would only require a bit of software to act as a driver passing the keyboard input to the operating system so either keyboard could be used or even have one hand on each.

sadly the QL's serial ports are best considered rudimentary at best. I certainly wouldn't chose to add external keyboard through them.

Hi,
After changing the keyboard membrane three times, I gave up, years ago.
At a show, Tony Firshman fitted an external keyboard, passing its cable through the microdrive extension slot, (onto SuperHermes ?). No problems since !
Dilwyn supplied the keyboard. Everything still works fine : SGC, ROMdisk, monitor and ED floppy reader. All microcassettes fail though...
But I only use the QL for testing backward compatibility of programs. QPC2 is oh so much faster to work with. But peek & pokeing demands recoding some code.
I still write QL code, as it is easy to test and debug before conversion to C++.
QL (keeps going on) forever !
Best Wishes,
Steve Poole.

stevepoole wrote:Hi,
After changing the keyboard membrane three times, I gave up, years ago.

My original 1985 QL has had its Keyboard membrane replaced only once, 15 years ago, and is still going strong.

Tobias

Pr0f wrote:sadly the QL's serial ports are best considered rudimentary at best. I certainly wouldn't chose to add external keyboard through them.

Could you elaborate? In my world if an rs232 passes bytes it works and a keyboard would pass bytes across it.

Ruptor wrote:

Pr0f wrote:sadly the QL's serial ports are best considered rudimentary at best. I certainly wouldn't chose to add external keyboard through them.

Could you elaborate? In my world if an rs232 passes bytes it works and a keyboard would pass bytes across it.

I could try -

serial comms (RS232) is provided by SER1 and SER2 on the QL - one was wired as DTE and the other as DCE, although they only implement DTR / CTS handshaking. The IPC chip handles only the receive side of the serial ports, the ZX8302 chip only the transmit side of the serial ports. The DTR and CTS handshaking for the transmit and receive sides of the interface are handled in the driver software, or the firmware (for receive) but not by hardware - so it's easily possible to overrun a buffer or lose a character. The buffers are not particularly large, so a faster device will easily overwhelm a QL. If anything else is using the ZX8302 - such as Microdrive access or network access - your serial ports won't be doing any output.

In the standard QL - you would be lucky to get 9600 baud running on one port, you certainly would not get 19200. Operating the 2 serial ports at different board rates is not possible on the standard QL.

The PS/2 protocol is a reasonably fast clocked (clk and data lines only) protocol, that would just about be managable to translate to a serial port running at 9600, providing it did not drop characters and could keep up. The AT keyboard interface protocol is similar to the Ps/2 and could be considered a subset, but the connector is different.