Hi Jan

This was posted on the QL Forum:


Repeated here:

Just a further note on the topic of PS/2 Splitter cables.

I recently purchased a Genius DX-110 Optical Mouse, on connecting the mouse to 
the Q68, via Splitter cable, stopped the Q68 booting up at the Ram Test stage, 
or more specifically at the point where the Q68 detects the PS/2 Mouse.

A Perixx Mouse 201-B PS/2 mouse works perfectly.

I examined the Genius DX-110 PS/2 Connector, which has these connections, it 
seems that the mouse connections use the Keyboard Data and Clock connections.:

Mouse Data connected to Keyboard Data 1
Mouse Clock connected to Keyboard Clock Pin 5

The Q68 expects the Mouse Data to be on Pin 2 and Mouse Clock on Pin 6 as per 
the so-called IBM standard:

This is the probable reason of the failure of PS/2 Mouse(s) (...Mice) on the 
Q68, the PS/2 Mouse to be connected to a PC uses the Keyboard Data and Clock 
connections and the PC PS/2 Controller chip on the PS/2 Interface decides 
whether the data supplied is keyboard or mouse and sends the data to the 
correct port.

In the case of the Q68, which uses Pins 2, 6 for Mouse Data and Clock signals 
will fail on the PC standard Mouse connections using Pins 1, 5 for Mouse Data 
and Clock signals.

A possible solution is to interchange Pin 1,2 and Pin 5,6 for the Q68 to use a 
PC PS/2 Mouse.

I have some PS/2 Splitter cables that do not work with the Q68, but 
interchanging 4 wires in the Mouse connector, get the splitter working.


On 29 February 2024 22:58:09 GMT, Jan Bredenbeek via Ql-Users 
<ql-users@lists.q-v-d.com> wrote:
>Hi Dilwyn,
>On 29-02-2024 19:05, Dilwyn Jones via Ql-Users wrote:
>> I might agree with that, were it not for the fact that there has been
>> no issue whatsoever with running SMSQ/E on it (apart from the fact I
>> have to configure it not to try to do fast SD card access).
>> Anyway, once Derek has been able to reprogram it, we'll know if it's
>> the software version or something else.
>I'm curious as to how you have connected the keyboard to the Q68. Is it 
>keyboard only or keyboard + mouse via a spiltter?
>When I use a splitter and connect the keyboard to the corresponding connector 
>on the spiltter, the Q68 freezes at the boot loader screen even if the mouse 
>is not connected. I have to reverse keyboard and mouse plugs to make it work. 
>Of course this has no relationship with Minerva or SMSQ/E (which hasn't even 
>started up yet) but it might have something to do with interrupts or firmware 
>(which I'm not familiar with, it's Peter's design).
>Also, you might check if the 5V power supply is sufficiently stable (the Q68 
>itself runs at 3V but the keyboard at 5V).
>I've got a reply today from Mark, he still has the freeze issue you describe 
>so you're not the only one with this problem.
>Best Regards,
>QL-Users Mailing List

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