MZ-80a disk options

[arnuphis]

So finally I have some drives/gotek that I can interface with my MZ-80b/2000 and they work great.

My MZ-80A has the expansion box but no card. It feels left out and I want to bring it into the 'modern' age. What card will I need to look for?

As far as booting, will it auto seek a floppy land put up a boot menu like the B/2000 or will I need to use another step?

Finally what Disk Basic will work?

Thanks!

[psmart]

The SFD-700 card I am developing works in the MZ-80A https://eaw.app/sfd700/ and also the MZ-700 albeit I still have some quirks to resolve, for instance, the card boots BASIC SA-6510 and F-DOS 7010 no issues on an MZ-80A but the Microtech CP/M fails to boot, I need to disassemble the FDC code and work out what it does differently to adapt the GAL logic. Not something that is going to be ready in the next few weeks due to my available time, possibly 2-3 months before I make a final cut of the board.

The original FDC card for the MZ-80A (MZ-80AFI) makes some tricks with the DRQ line and the boot ROM where the DRQ when set selects a different part of the ROM (typically a JP (IX) JP (IY) instruction). The setup and hold of the A10 line to the ROM is not a 1:1 relationship with DRQ, so is processed in a gatearray on the MZ-80AFI card. Sharp did this because the 2MHz Z80 is too slow to read the status register of the MB-8866 and when DRQ set then read the data register and maintain a constant data flow without overrun.

[psmart]

Pictures of the SFD-700.

Some issues, I used a Russian 74LS04 as I couldnt get 74LS04 devices in quantity from Signetics/TI, big mistake, I fail to bias it reliably and so cannot get it to oscillate. The dev board, 3rd photo, I had to hard wire an SMD oscillator to further the project!!!

[S_U_C]

The IPL loads the boot sector (1) 256 bytes and the IPL header loads sectors 1 and 2 both are 256 bytes, total 512 bytes the IPL header executes code in sector 1 and in sector 2.
the rest of the disk is in 512 byte sectors 10 per track numbered 1-10 and 11 to 20 skew 2 ordering.
ie. 1,3,2,4,5,6,7,8.9,10 (head 1) and 11,13,12,14,15,16,17,18,19,20 (head 2)
However the boot track sectors are order , 1,2,7,3,8,4,9,5,10,6 just to confuse things.

[S_U_C]

sorry typo error skew 2 ordering is 1,6,2,7,3,8,4,9,5,10 and 11,16,12,17,13,18,14,19,15,20
boot track order was correct 1,2,7,3,8,4,9.5,10,6

[psmart]

Thank-you for this info, appreciated. It will help as I want to encapsulate Microtech CP/M in my ROM FS. I've designed a new version of the SFD700 with additional on-board FlashRom to make it more versatile.
I discovered this issue with Microtech, I was using an AFI ROM from sharpmz.org and the second 1K didnt have the correct JP (IY) code, basically identical JP (IX), a dump from my original card ROM fixed the issue.

[JulianS]

Thank-you for this info, appreciated. It will help as I want to encapsulate Microtech CP/M in my ROM FS. I've designed a new version of the SFD700 with additional on-board FlashRom to make it more versatile.
I discovered this issue with Microtech, I was using an AFI ROM from sharpmz.org and the second 1K didnt have the correct JP (IY) code, basically identical JP (IX), a dump from my original card ROM fixed the issue.

Hi there - is it possible to purchase a populated SFD700? And would it require an expansion box / adapter for use in a MZ-700?

Julian.