Search found 2473 matches

by Dave
Tue Mar 31, 2020 7:31 am
Forum: Hardware
Topic: QL Add-on ROM
Replies: 34
Views: 1072

Re: QL Add-on ROM

You could have a physical witch to connect /WR. If you tie it to 5V it can’t be written. A mechanical pull-up.
by Dave
Mon Mar 30, 2020 6:44 pm
Forum: Hardware
Topic: QL Add-on ROM
Replies: 34
Views: 1072

Re: QL Add-on ROM

May I propose thinking about this in a slightly different way? What if instead of a flash IC (20 year retention guarantee) you used a 128K low power SRAM and CR2032 battery as back-up power? In standby, the SRAM would retain contents using microAmps. The battery would last 15 or 20 years. If you spl...
by Dave
Sat Mar 28, 2020 10:13 pm
Forum: Hardware
Topic: QL-SD ROM
Replies: 14
Views: 440

Re: QL-SD ROM

Though I can't think of a use case where someone would use a QL-SD and want a Miracle hard drive.
by Dave
Sat Mar 28, 2020 7:32 pm
Forum: Hardware
Topic: QL-SD ROM
Replies: 14
Views: 440

Re: QL-SD ROM

It's not the first QL hardware to program its own flash, but it will be the first released hardware, yes.
by Dave
Sat Mar 28, 2020 4:14 pm
Forum: Hardware
Topic: QL Add-on ROM
Replies: 34
Views: 1072

Re: QL Add-on ROM

I have programmed flash off the QL bus, during multi-tasking, without problems. If you recall my idea a few years ago of having multiple CPUs mapped through dual port SRAM to areas of the QL's memory map, I did a fair amount of work on it. I ended up using a small flash as a persistent system-progra...
by Dave
Fri Mar 27, 2020 4:05 am
Forum: General QL Chat
Topic: Comparing Sinclair QL to Commodore 64
Replies: 25
Views: 612

Re: Comparing Sinclair QL to Commodore 64

If I had to pick a machine that was most line the QL, I would pick the Coleco Adam. Similarities: Both have two CPUs. The Adam 2nd CPU, used for system IO and memory management, is a 6801 - a small ROM microcontroller version of the 6800. In the QL, it's an 8049. Both communicate through an internal...
by Dave
Wed Mar 25, 2020 9:04 pm
Forum: The Off-Topic Section
Topic: Today I Received...
Replies: 199
Views: 18789

Re: Today I Received...

XorA wrote:I wonder if this could be QL related purchase?


Tease. :o
by Dave
Wed Mar 25, 2020 8:59 pm
Forum: Hardware
Topic: QL Add-on ROM
Replies: 34
Views: 1072

Re: QL Add-on ROM

I don't have any miniplanes left, sorry. I did a 128K battery backed SRAM with write protection a few years ago, for my own personal use. I'll dig it out. It sounds exactly what you need. If I can find the PCB files, I'll publish them. It used two 628512 to implement 896K, with the top 128K write pr...
by Dave
Fri Mar 20, 2020 5:22 pm
Forum: Compatibles Corner
Topic: Does ITX Cases work for any QL Compatible Motherboard
Replies: 15
Views: 1731

Re: Does ITX Cases work for any QL Compatible Motherboard

Mini-ITX cases do not work for any currently available QL or clone.

The Q68 can be bodged into anything, but "bodge" is the operative word and a mini-ITX case is still massive overkill for the Q68.
by Dave
Sun Mar 08, 2020 2:04 pm
Forum: Compatibles Corner
Topic: Q68 Serial devices
Replies: 71
Views: 3110

Re: Q68 Serial devices

It does sound like the power supply. You plug the keyboard in and it delivers the extra current, but then after a few seconds it hits the thermal limit and starts current limiting?