glitch
Veteran Member
I've been working on writing up my process of getting CP/M bootstrapped for the SD Systems VersaFloppy II using Bruce Jones' code that Herb Johnson has on his site. I've had it working for a good while (geneb has a system I set up with it) but I've just not had the time to get it all together. Today, I uploaded cleaned-up code and 5.25" diskette images for the TDL SMB or SMB-II:
github.com
I did this customization for a hobbyist in Canada, he's going to be using a TDL ZPU in his IMSAI and wanted an I/O board and floppy controller, so I suggested either the TDL SMB or SMB-II and the VersaFloppy II. The VersaFloppy II is an excellent choice if you're going to be running a Z80. Here's pictures of the test system running today:
I usually don't do IOBYTE implementations (just leave the skeleton code in place) since there's a huge variety in what people may or may not have for I/O devices, but the SMB and SMB-II provide a pretty complete set of interfaces, and the Zapple monitor has its own IOBYTE support too! I customized the CBIOS to read from the Zapple IOBYTE holding register, 0x76. The CP/M device assignment follows the Zapple assignment pretty closely. I haven't tested cassette for PUN: and RDR: yet but it just calls out to the ROM routines.
Since there's IOBYTE support, that means Kermit-80 with the "Generic CP/M 2.2" overlay works! I also did PCGET/PCPUT customizations that can use either the TTY or CRT ACIAs.
Finally had diskettes I felt were complete enough to put typewritten labels on this afternoon:
I will try and update this thread as I get more disk images online. I have a bunch of customizations that aren't in the Github repo yet, and the others that are there are just the CBIOS source at the moment. I'll be wrapping up customizations for the SD Systems SBC-200 this week, so those should be up soon.
While 5.25" diskettes are fine, the real high point of VersaFloppy II interfacing is 1.44 MB PC-style drives. With a simple modification to a PC twist-type cable, you can use unmodified 1.44 MB drives with HD media and get a fairly impressive 1.66 MB per diskette -- and that's at 77 tracks, not even using all 80! That's my usual personal method of using the VersaFloppy II, but in the TDL SMB customization the guy getting the boards wants to use 5.25" drives.
I need to modify the formatting program to use 40 tracks on 5.25" -- the existing code only formats 35 tracks for compatibility with very old drives. I like the compatibility aspect, but it'd be nice to get a little more storage on there. The formatter also won't do 1K sectors on 5.25", which I think shouldn't be a problem to support.
GitHub - glitchwrks/versafloppy_2_cpm22: CP/M 2.2 for the SD Systems VersaFloppy II
CP/M 2.2 for the SD Systems VersaFloppy II. Contribute to glitchwrks/versafloppy_2_cpm22 development by creating an account on GitHub.
github.com
I did this customization for a hobbyist in Canada, he's going to be using a TDL ZPU in his IMSAI and wanted an I/O board and floppy controller, so I suggested either the TDL SMB or SMB-II and the VersaFloppy II. The VersaFloppy II is an excellent choice if you're going to be running a Z80. Here's pictures of the test system running today:
I usually don't do IOBYTE implementations (just leave the skeleton code in place) since there's a huge variety in what people may or may not have for I/O devices, but the SMB and SMB-II provide a pretty complete set of interfaces, and the Zapple monitor has its own IOBYTE support too! I customized the CBIOS to read from the Zapple IOBYTE holding register, 0x76. The CP/M device assignment follows the Zapple assignment pretty closely. I haven't tested cassette for PUN: and RDR: yet but it just calls out to the ROM routines.
Since there's IOBYTE support, that means Kermit-80 with the "Generic CP/M 2.2" overlay works! I also did PCGET/PCPUT customizations that can use either the TTY or CRT ACIAs.
Finally had diskettes I felt were complete enough to put typewritten labels on this afternoon:
I will try and update this thread as I get more disk images online. I have a bunch of customizations that aren't in the Github repo yet, and the others that are there are just the CBIOS source at the moment. I'll be wrapping up customizations for the SD Systems SBC-200 this week, so those should be up soon.
While 5.25" diskettes are fine, the real high point of VersaFloppy II interfacing is 1.44 MB PC-style drives. With a simple modification to a PC twist-type cable, you can use unmodified 1.44 MB drives with HD media and get a fairly impressive 1.66 MB per diskette -- and that's at 77 tracks, not even using all 80! That's my usual personal method of using the VersaFloppy II, but in the TDL SMB customization the guy getting the boards wants to use 5.25" drives.
I need to modify the formatting program to use 40 tracks on 5.25" -- the existing code only formats 35 tracks for compatibility with very old drives. I like the compatibility aspect, but it'd be nice to get a little more storage on there. The formatter also won't do 1K sectors on 5.25", which I think shouldn't be a problem to support.
