General Stuff(tm)

[stephen_usher]

It turns out that the software doesn't set the baud rate itself, so I've written a SuperBASIC loader which sets it and sets the serial port before calling the program.

I checked with the ATI6 on the modem that I was connected at 1200 baud and...

Well, unfortunately no difference.

[stephen_usher]

On another front... I was only home this afternoon as a repair man for the garage door was supposed to arrive so took a half day off work.

I've just had an automated call telling me that they won't be coming today but sometime tomorrow with a one hour warning... so I'm going to lose another leave day from the small number I have left which I'm trying to save for my Dad's house sale.

[stephen_usher]

Got the QL talking to Viewdata services!

I had to use the 'ser2e' device to get even parity.

IMG_3780.jpeg

IMG_3781.jpeg

[stephen_usher]

Finally, at last I've put my thinking cap on for the redesign and simplification of the Computer One floppy disk interface for the ICL OPD.

Out will go the 74LS74, 74LS38, 74LS10, 74LS02 and 74LS04 and in will come a 16V8 GAL and a second 74LS06. So that will decrease the chip count by three.

The GAL can do all the address decode stuff and power the floppy SIDE and SEL0/1 lines. The 74LS06 will replace the 74LS38 and the 74LS04. I will just need one of the spare 1K pins on the pull-up resistor matrix for the clock output from the 74LS06.

[stephen_usher]

Right, redesign complete... Hopefully.

New schematic:

OPD-Computer-One-Disk-Interface-schematic.jpg

Hopefully it'll look like this and work. ;-)

OPD-Computer-One-Disk-Interface.jpg

It's a lot shorter than the first iteration of the design so shouldn't get in the way of the monitor and also not stress the ROM port connector as much. I've also fixed the M/B connector so that it's on the correct side of the board (component side) so I should be able to 3D print a case for it which fits into the ROM expansion unit snugly.

[stephen_usher]

Boards ordered... and they're small enough to be $5 for 5 from PCBWaaay.... Well, slightly less as now have a small discount. Works out at about £25 inc. shipping.

[stephen_usher]

*grumble* The PCB manufacturing is slow today. Only 18% done (laminate cutting) so far and 12 hours between manufacturing instruction and the start. Looks like they may be busy at the moment. Probably means that they won't arrive until next week now. Oh well.

[HigashiJun]

NIce progress with your QL !

PCBWay was always slower than JLCPCB for me...

[stephen_usher]

NIce progress with your QL !

PCBWay was always slower than JLCPCB for me...

It's definitely variable depending upon the time of year but usually it is within 24 hours and across the World within the working week.

[stephen_usher]

I've been thinking... If I can get the ROM disassembled there's a possibility that I can change the design to include some SRAM to hold the slave blocks and working space, freeing up the main memory and allowing BASIC and configuration utilities to load. But that's a big IF.

Also I'd make the floppy format correct FAT12 so that it could read and written to by PCs...