Search found 393 matches

by Pr0f
Tue Oct 22, 2019 7:07 am
Forum: The Off-Topic Section
Topic: Happy Birthday!
Replies: 192
Views: 70093

Re: Happy Birthday!

Happy Birthday to Derek and XorA - just spotted your names at the bottom for today :-)
by Pr0f
Fri Sep 27, 2019 3:28 pm
Forum: Hardware
Topic: DIY Fpu Unit for STFM
Replies: 28
Views: 4257

Re: 74HCxx vs 74LSxx

I believe some QL emulators use the A-line instructions as a form of trap to replace I/O routines in QDOS with code that looks after the host OS functions
by Pr0f
Thu Sep 26, 2019 10:59 am
Forum: Hardware
Topic: DIY Fpu Unit for STFM
Replies: 28
Views: 4257

Re: 74HCxx vs 74LSxx

That;s just 8 FPU's !

They never did seem to extend this co processor functionality beyond memory manger and FPU - a graphics GPU co processor would have been a useful addition ;-)
by Pr0f
Mon Sep 23, 2019 7:51 am
Forum: Software & Programming
Topic: Read N bytes from a channel to a memory buffer
Replies: 7
Views: 557

Re: Read N bytes from a channel to a memory buffer

didn't Simon Goodwin's MEM device offer the ability to write to memory as a device - not entirely sure how safe this would be given that the way QL uses memory, you could be writing over anything (slave blocks, Basic, loaded drivers, and there is no memory protection as such, unless the MEM device v...
by Pr0f
Fri Sep 13, 2019 10:56 pm
Forum: Hardware
Topic: 2 ql's and roms ?
Replies: 4
Views: 552

Re: 2 ql's and roms ?

Early versions of the QL had a 3rd ROM in the ROM port and the 2 internal ROM sockets filled - these were 16K ROM's or EPROMS as the original intention was to get the OS and BASIC into 32K, but the ROM grew to 48K. The ROM dongle was moved internally, hence the piggy backed ROM's and flying lead - e...
by Pr0f
Fri Sep 13, 2019 6:23 pm
Forum: Hardware
Topic: 2 ql's and roms ?
Replies: 4
Views: 552

Re: 2 ql's and roms ?

You can also solder 2 ROM's on top of each other if they are a set, as both sockets are in fact wired the same way, but the jumpers need to be wired for the 2 ROM setup - the advantage of doing this is it keeps one ROM socket free, for QL-SD or similar interfaces.
by Pr0f
Wed Aug 21, 2019 11:22 am
Forum: Hardware
Topic: Issue 8 discussions...
Replies: 140
Views: 16700

Re: Issue 8 discussions...

Did someone not have a 'recreated PCB' for the issue 5 or issue 6 board as a bare pcb - i am sure I haven't dreamt that... I could use one as I have a QL that's got some damaged tracks under the memory, and as a fix I am contemplating a piggy back board lifting the ZX8301 onto the board with a singl...
by Pr0f
Fri Aug 16, 2019 12:12 pm
Forum: Hardware
Topic: MAB 8049H P A038 comapible?
Replies: 10
Views: 1288

Re: MAB 8049H P A038 comapible?

Hi, Very interesting read, but it does not say that Laurnce Reeves produced a debugged more efficient version of the 8049 called Hermes. Personally, I would use Hermes over the 8049, it works better in the QL and is still available on Sellyouretro. No - but I only meant to explain that Hermes is us...
by Pr0f
Fri Aug 16, 2019 8:48 am
Forum: Hardware
Topic: MAB 8049H P A038 comapible?
Replies: 10
Views: 1288

Re: MAB 8049H P A038 comapible?

by Pr0f
Fri Aug 16, 2019 8:46 am
Forum: Hardware
Topic: MAB 8049H P A038 comapible?
Replies: 10
Views: 1288

Re: MAB 8049H P A038 comapible?

With Micros's like this they offered them in various formats: EPROM piggy back - these have a socket on the back of the chip itself for the program memory EPROM Internal - device has an EPROM for Program memory on board the chip and has a clear window to allow UV erase EPROM OTP - this is the same a...