General Stuff(tm)

[rubber_jonnie]

I'm just hoping that the clock circuit actually works for a start. Without that it's just going to be a ROM cartridge with a lot of extra logic.

With this board I'm just verifying the reverse engineering.

I'm thinking that with the Mk.II I'll put the WD1772, clock and FDC logic onto another board, which will make the board which plugs into the OPD ROMpack smaller and put less strain on the connector. It will also allow a future second board which will be a RPi Pico based WD1772 simulation with images held on SD card or similar, so there will be no need to have a Gotek or real drives. I will also put all the address decode logic into a GAL, to reduce the chip count.

Sounds like quite the project, good luck with it, I'm very interested in the outcome. I can build stuff, just not design, so I rely on clever folks like you to come up with projects for me :)

Oh, and the QIMSI issues are really about the documentation. I've had someone say on the QL Forums that it shouldn't be up to the hardware developer to write documentation, they have better things to do. *sigh* Silly people. Only the designer really knows the foibles and work arounds for the device.

That is really just daft, if the designer doesn't document it, how on earth is somebody else supposed to who doesn't have the in depth knowledge?

[stephen_usher]

[Sounds like quite the project, good luck with it, I'm very interested in the outcome. I can build stuff, just not design, so I rely on clever folks like you to come up with projects for me :)

Well, in this case I just had to trace the wires on the old PCB in effect, and use photographic evidence for the resistor values and locations on the board (to work out what they connected to.

To be honest though, 74 series logic is electronic Lego. You plug the right bricks in the right order and you get a something which should work. :-) ("should" is the operative word.)

Oh, and the QIMSI issues are really about the documentation. I've had someone say on the QL Forums that it shouldn't be up to the hardware developer to write documentation, they have better things to do. *sigh* Silly people. Only the designer really knows the foibles and work arounds for the device.

That is really just daft, if the designer doesn't document it, how on earth is somebody else supposed to who doesn't have the in depth knowledge?

I know. I know. The builder was the person getting uppity, the designer was really reasonable.

[stephen_usher]

Come one PCBWay, finish making my boards, they've been stuck at 33% for hours. :-)

[rubber_jonnie]

Come one PCBWay, finish making my boards, they've been stuck at 33% for hours. :-)

It's always the way :)

[stephen_usher]

The boards have just been picked up by DHL, so they're on their way. I'd better order all the 74LS chips. I'm pretty sure I've got 74LS02s and 04s but I don't have a 10, 38, 74 or a 175. I think I have a 245. And I need a right-angled 30 way socket.

[stephen_usher]

Well, that wasn't cheap, buying all the chips and sockets. Admittedly I overstocked on some of the common ones.

At least I know I will have enough to build stuff over Christmas, assuming the boards arrive. (OK, I only have one 1772. I should have another somewhere which I took out of the TT when I fitted and AJAX chip a few years ago, but goodness know where that is.)

[rubber_jonnie]

Well, that wasn't cheap, buying all the chips and sockets. Admittedly I overstocked on some of the common ones.

At least I know I will have enough to build stuff over Christmas, assuming the boards arrive. (OK, I only have one 1772. I should have another somewhere which I took out of the TT when I fitted and AJAX chip a few years ago, but goodness know where that is.)

Nice knowing you have what you need though, I hate getting to a spot in a project and finding I'm short of something and have to down tools and wait for parts.

[stephen_usher]

Well, maybe I'm getting ahead of myself but I've found some floppy disk images for the One Per Desk on-line which contain copies of the configuration utilities. As they're 720K FAT12 images I was able to open them as virtual drives on my MacBook Pro and have a look at their contents. Looks promising.

Of course, as they're 720K FAT12 format disks it'll mean that it's a doddle to transfer files using the TT. Just upload over the network using UIPtool and copy onto the floppy, or vice-versa. I love it when there's synergy between the different retro-computing strands.

[stephen_usher]

The 74LS74s and 74LS175s have arrived from Farnell. The RS delivery is due at lunchtime. That includes the 8MHz crystal oscillator, the rest of the TTL logic and the right-angled 30 pin connectors.

[stephen_usher]

And the rest has arrived.

I think I now have enough 74LS04s to last a lifetime. :-)