Search found 2610 matches

by Dave
Thu Jun 24, 2021 1:03 am
Forum: Software & Programming
Topic: Q68 QoE Ethernet Driver
Replies: 66
Views: 6523

Re: Q68 QoE Ethernet Driver

A counter would be easy to implement. The choice of signals available at the CPU socket are quite limited, though.
by Dave
Wed Jun 23, 2021 5:13 pm
Forum: Software & Programming
Topic: Q68 QoE Ethernet Driver
Replies: 66
Views: 6523

Re: Q68 QoE Ethernet Driver

Ok. That's 2kHz. I can do that. Obviously it's not going to be 50% duty cycle. I need to go off and think a little to do it correctly. As a code defined ticker it can be altered later.

The ticker is an interrupt. What level interrupt should it be?
by Dave
Wed Jun 23, 2021 1:33 pm
Forum: Hardware
Topic: Multiplexer chip
Replies: 5
Views: 206

Re: Multiplexer chip

That will definitely not work in a QL.
by Dave
Tue Jun 22, 2021 6:54 pm
Forum: Software & Programming
Topic: Q68 QoE Ethernet Driver
Replies: 66
Views: 6523

Re: Q68 QoE Ethernet Driver

I have a rather massive quantity of 8Kx8 SRAMs, and can throw one on the card to give it its own private memory area for the stack. I can provide a ticker, and have provided for that. All I need is a target frequency for the ticker. I can divide it from the CPU clock or ethernet clock, or something ...
by Dave
Thu Jun 10, 2021 8:25 pm
Forum: Hardware
Topic: Mystery card reveal!
Replies: 6
Views: 325

Re: Mystery card reveal!

I just got a reply from the seller. They bought the QL in a batch of items from an estate sale. They don't have any further info. I've asked them if they can say the name or location of the estate sale. No reply as yet.
by Dave
Thu Jun 10, 2021 6:43 pm
Forum: Hardware
Topic: Mystery card reveal!
Replies: 6
Views: 325

Re: Mystery card reveal!

I'm heading out the door this evening for a road trip to Pittsburg to meet Phoebus. I'll check it out when I get back. It's a late US QL in very crisp condition that was formerly owned by a heavy smoker. Some detox required.

I'll be back around the 22nd.
by Dave
Thu Jun 10, 2021 5:37 pm
Forum: Software & Programming
Topic: Q68 QoE Ethernet Driver
Replies: 66
Views: 6523

Re: Q68 QoE Ethernet Driver

Does 'QoE Ethernet driver for Q68' imply that the driver won't work on the QL implementation of the hardware?
by Dave
Thu Jun 10, 2021 5:36 pm
Forum: Hardware
Topic: Mystery card reveal!
Replies: 6
Views: 325

Re: Mystery card reveal!

Interesting observations:

It's a four layer PCB. It's translucent so Inner2 is visible, and Inner1 is partially visible and easy to work out.

There is a number "3" scratched into the back of it, on the left. There might be very few of these.
by Dave
Thu Jun 10, 2021 5:29 pm
Forum: Hardware
Topic: Mystery card reveal!
Replies: 6
Views: 325

Mystery card reveal!

The US QL came, and the card is unlike anything I've personally seen before.

Here it is in full HD:

IMG_2418.jpeg

IMG_2419.jpeg


Sooo, a 512K RAM expansion using two 256K SIPs. The memory ICs are MT1259EJ-12 page mode DRAMs 256Kx1. The name is also new to me: M Zenkar.

Enjoy!
by Dave
Wed Jun 09, 2021 4:53 pm
Forum: Hardware
Topic: QL MicroDrive electrolytic caps
Replies: 11
Views: 525

Re: QL MicroDrive electrolytic caps

C9/11 and C10/12 don't conflict with anything as I recall. As long as they're shorter than the 7805 itself, there shouldn't be any mechanical problems.

For everyone else:

C9/10 are a .47uF electrolytic
C10/12 are a .22uF in UK/EU designs and a .47uF on a couple of my Samsung US QLs.