Myarc DDCC-1 (Modification Question)

[Omega-TI]

With the Myarc DDCC-1 clone slated to come out sometime, hopefully in the not to distant future, I was looking up the original card on the Internet and found the photo below.

 

I have a couple of questions for you experts & owner's out there.

 

It's obvious that the labeled chip has something to do with the 80 track upgrade, but that little chip stuck to the PCB with the wires soldered to the card edge connectors... is that part of the 80 track mod on the original card as well... or is it something else?

 

 

 

[Shift838]

Not sure what that is. I know for me to get the 80 track upgrade on mine it was a simple EPROM upgrade.

[sparkdrummer]

Don't know what the wiring is about, but to do an 80 track upgrade you just pop in a different EEPROM.

[+InsaneMultitasker]

The card in the photo has been modified to decode AMA/AMB/AMC address lines.

[+mizapf]

<gulp> The DDCC-1 does not decode AMA/AMB/AMC? Why does it work with my Geneve?

[+InsaneMultitasker]

The Geneve Genmod upgrade requires ALL peripheral cards to follow TI's AMA/B/C decode specifications. IIRC, early Myarc FDCs, the Horizon RAMdisks, some Rave cards, and the CorComp FDCs do not decode these address lines. There may be other configurations that require the decode but Genmod was the primary driver of this modification.

[+mizapf]

Thinking a bit longer about it ... I remember that on disk accesses I get occasional burps and blobs from the speech synthesizer, most likely because the adaptor board on which the speech synthesizer sits was created by me, also being ignorant about AMA/B/C. When there are accesses that hit a mirror of 0x79400, the synthesizer reacts. However, this only occurs for accesses into the box, because the other accesses to the onboard RAM are not seen in the box. I'm not fully certain about which accesses are seen in the box on the stock Geneve; I only know that the Genmod makes all of them visible.

 

Accordingly, the ports of the DDCC-1 are mirrored in the memory space if there is no AMA/B/C decoding. The reason that nothing bad happened until now is that there is no activity in the box apart from floppy or SCSI accesses, or speech, and that I don't have a Genmod.

[+Schmitzi]

H,

 

This here is My Ark 80 tracker Would it run in my PFMmodded Geneve, also in a normal TI/PRB ?

Is there anything possible to optimize, because changing cooler and capa´s for routine at the moment ?

 

Do I have this AMA/B/C decoding ? Or need ?

 

♫♪ I want all ♪ I want it now ♪♫

 

[Omega-TI]

The card in the photo has been modified to decode AMA/AMB/AMC address lines.

 

Thanks. It had me puzzled.

[+InsaneMultitasker]

H,

 

This here is My Ark 80 tracker Would it run in my PFMmodded Geneve, also in a normal TI/PRB ?

Is there anything possible to optimize, because changing cooler and capa´s for routine at the moment ?

 

Do I have this AMA/B/C decoding ? Or need ?

 

♫♪ I want all ♪ I want it now ♪♫

 

Assuming you mean Myarc 80 track controller Yes, it will work just fine with a PFM modified Geneve and in a stock system.

 

If I remember right, you have the double-stack Atmel 29c010 revision, which is earlier than the final 29c040 512K single chip version. You cannot update the boot BIOS to the lastest code (due to size limitations) however, you CAN still use the program SCSI4PFM and SCSISPLIT to load a later MDOS (Geneve OS) into the flash memory. Look for the MDOS 4.00S distribution pack as I am pretty sure I included the files there. If you cannot find the files, PM me and I'll look around when I have time.