Changed the header pins and the hardware is now reliable. Got a little further. The system now reads the first sector of the "drive" and decides that it's not bootable. I found the virtual floppy with the HD formatter on it and I've got it as far as trying to format the first track of the ...

I'm going to have to replace the headers on the RAM board with longer ones. The DuPont connectors just won't stay on and connect reliably with the current ones.

Here you are...

Got to the point where I needed to attach the /INT2 interrupt line... Then things stopped working again due to an iffy connection somewhere on the breadboard. *sigh*

Time for bed.

I'm working through the logic now.

I dislike Python I'm finding, especially when dealing with byte data.

I'm going to have to write a set of bit_set() and bit_clear() procedures to clean things up.

It does do a memory test. I've seen the X's

I've done enough of the logic that the machine *thinks* that it has a 10MB hard drive, most of the time, if I start the Pico code from scratch every time. Still, progress. The system can't actually read or write anything yet other than the WD1010-05 virtual registers and the data buffer, but still. ...

I'm finally getting somewhere. I've now got data flowing and it seemingly it's sane. I had to correct some GAL code for the memory board for the I/O read-write control line for a start. Secondly I discovered that I'd wired up the address bus slightly incorrectly... oh and forgot to hook up the selec...

I think that I also need to download a newer version of micropython as it's not reliably reading or writing values to the GPIO pins when run in a program. (The command line is fine.)

Well, it would help if I connected the right output pin from the GAL to the /OE lines on the 244 and 245 wouldn't it? Still, the 74LVC244 at 3.3V seems to be too slow to react to the output enable lines. The /G1 and /G2 levels drop for 400ns but the low input doesn't get translated to the output. If...