#159 Expand the support for Professional DOS R3/R4 1541 to include Datel Disk Demon

[Anonymous]

Recently the Datel Disk Demon kernal and drive ROMs have been made avilable by nialled over at Lemon64 (https://www.lemon64.com/forum/viewtopic.php?t=82454&start=75).
This is a revision of the Mikrotronic Professional DOS R4 1541 Parallel fast loader.

diskdemon_Single-Kernal-8k.bin --- Datel Disk Demon C64 kernal ROM (8K)
DISKDEMON_Original_1541_ROM.bin --- Datel Disk Demon 1541 drive ROM (32K)
kernal_userport_release_4.rom --- Professional DOS R4 1541 C64 kernal ROM (8K)
expanded_1541.rom --- Professional DOS R4 1541 drive ROM (16K)
RapiDOS_pro_20_kernal.bin --- RapiDOS Professional v2.0 C64 kernal ROM (8K)
RapiDOS_pro_20_drive.bin --- RapiDOS Professional v2.0 1541 drive ROM (32K)

I have tested different combinations of Prof DOS/RapiDOS Pro/Disk Demon ROMs with the following result:

All kernal ROMs work with either Prof DOS or RapiDOS Pro drive ROMs.
No kernal ROM works with Disk Demon drive ROM.

Loading a directory listing works with the Disk Demon drive ROM, but attempting to load a PRG fails after a second or two, with the drive indicator blinking continiously.

[PiCiJi]

put it on todo list

[PiCiJi]

Is there any information yet on how the ROM is mapped? or any more infos ?
The schematics don't reveal everything.

[Anonymous]

Doing a comparison between the Disk Demon drive ROM and the RapiDOS Pro drive ROM shows:
32433 same byte(s)
150 left orphan byte(s)
150 right orphan byte(s)
185 difference byte(s)
So I would have assumed they are mostly the same and rather just a revision/variation. I don't have any more info but I can ask "nialled" if he has additional info.

[Anonymous]

Hi, I don't know if any of this will help but I have been re-working the original Disk Demon and Professional DOS PCBs.

There are basically two ROMs in a Disk Demon/Professional DOS PCB; the 32k EPROM and the 82S123 PROM that I have replaced with an ATF16v8 PLD in Disk Demon (and plan to do the same in Prof DOS)

The PLD/PROM programming is the same for Disk Demon and Professional DOS so all the differences are down to a few hardware alterations and the EPROM.

I have assumed that the differences between the Disk Demon EPROM and the Professional DOS EPROM are two fold:

1) The Disk Demon EPROM has a complete copy of Commodore DOS in it as well as the Disk Demon DOS (Professional DOS for the 1541 does not include CBM DOS which is why it is a 16k EPROM)

2) A couple of address lines (address lines 1 & 14) that are used in Professional DOS have been re-assigned in Disk Demon. I assume it is probably this that accounts for the changes to the Disk Demon EPROM code vs the Professional DOS code.

A1 is now used solely to select the DOS version (CBM or Disk Demon). In Professional DOS, A1 was used along with A2 & A14 to select the processor speed (1MHz or 2 MHz)

A14 is now only used to control the PLD/PROM in Disk Demon. In Professional DOS, A14 was also used along with A2 & A1 to select the processor speed (1MHz or 2 MHz). As A14 was never connected to the ROM, it probably does not account for the differences to the EPROM.

I have attached my reworked schematics for both Disk Demon and Professional DOS 2. Other than the new routing for A1 & A14 the only hardware diffences are centered around U2, U3 & U6. I have also attached a PROM dump for the 82S123/ATF16v8.

The Disk Demon 1541 ROM file has already been uploaded.

Please note, I am not a hardware engineer and there are parts of the design that I do not understand yet.

[Anonymous]

It looks like two of the attachments are missing so I am going to have another go

[Anonymous]

I don't what I am doing wrong but I only seem to be able to upload one attachment at a time

[PiCiJi]

Thanks for the infos.

[PiCiJi]

nightly: support disk demon speeder
The PROM dump of the ATF16V8B from the Excel file was the missing link.
As with the other speeders, compatibility is mediocre; for instance, Zak McKraken repeatedly asks for the next disk. The speeder can be disabled using @D0 , though Zak still won't load even then. (boot disk never prompts for the next disk.) This is something that should be verified using original speeder hardware; there might be a bug in Denise regarding how the speeder is hidden.

hint: insert "DISKDEMON_Original_1541_ROM" as expanded ROM and leave 1541 slot empty.
empty slots uses default firmware. lower 8k of default 1541 firmware are needed.

[Anonymous]

Sweet, can confirm it works. Have not made any extensive testing but it loads disks now.
I will try to confirm how Zak McKraken acts on real hardware eventually, if/when I can get my hands on the actual hardware.

[Anonymous]

My rework of the Disk Demon hardware is pretty much an exact copy of the original apart from the use of a PLD in place of the BiPolar PROM. Obviously the PCB layout is new but it is essentially the same schematic as the original.
I will be making the Gerbers available once I am sure the PCB is as close to 'perfect' as I can get it. Do you want me to upload them here?
Also, please forgive what may be a dumb question but what is Zak McKraken?
NiallEd

[PiCiJi]

I will be making the Gerbers available once I am sure the PCB is as close to 'perfect' as I can get it. Do you want me to upload them here?

yeah thanks.

Zak is an adventure game. Most speeders have trouble with it. I mean, it only runs with Jiffy and Dolphin.