JiffyDos from the ground up

[sirmorris]

Hi all,

Having kitted out my 128 with sd2iec i'm now looking to speed things up a little.

Having looked around the forums I haven't found the answer to my question here, apologies if I'm missing something or asking something that is forbidden - though from some of the other posts here I don't think it is For the record I'd buy if I could.

It appears that I have to fit replacements for the 8k kernal and 16k '64 basic devices. These are chips with IDs 318020 and 251913 respectively. From the schematic there will have to be some pin remapping if I use 27c eproms but nothing devastatingly hard. Is there a known supplier of 23 series chips?

Can anyone add anything to this please? Specifically the switching, though I think I could possibly work that one out.

Many thanks in advance.

[airship]

Actually, you don't touch the BASIC chip. You replace the computer's Kernal and the ROM chip in each of the drives you want to control.

If you use 27-series EPROMs (and you will - the older ones are too hard to come by) you'll need a 28-to-24 pin adapter. There are plans for making these online, either by burning a PCB or just hacking up an adapter using a couple of sockets. Sometimes you see them for sale, but not often. Nick at the 64HDD site sells adapters, but he wants $20 apiece. (Out of MY price range!)

How to make one from two sockets: http://symlink.dk/nostalgia/c64/rom/
PCB pattern for burning your own boards: http://freenet-homepage.de/x1541/hardware/2364.html
64HDD $20 adapter: http://www.64hdd.com/shop/shop-roms.html
JiffyDOS binaries and installation instructions (Andrew Wiskow's site): http://cottonwood.servebbs.com/wiskow/

If you use a larger EPROM, you can also install a switch in your computer and/or drive so you can switch back and forth from the original ROMs to JiffyDOS.

[sirmorris]

Thanks for that!

I've checked out all the information at Andrew Wiskow's site but unless I'm blind/stupid I can't see anything for the 128.

I'm talking to an SD2IEC board rather than a 1541 so there'll only be one chip to swap out, I guess. Will it all 'just work' in '64 mode?

[airship]

Yeah, for SD2IEC you only need the Kernal ROM. JiffyDOS support is built into the SD2IEC.

The C128 version (and all the rest) are in a single zip file called 'Collection of JiffyDOS ROMs'

[Andrew Wiskow]

I've checked out all the information at Andrew Wiskow's site but unless I'm blind/stupid I can't see anything for the 128.

Like Airship said, just click on the "Collection of JiffyDOS ROMs" link to get the zip file.  The C128 JiffyDOS ROM, as well as most disk drives, are all there.

[airship]

Is there an echo in here?

[Andrew Wiskow]

Is there an echo in here?

Yes, there certainly is. 

[RobertB]

Yes, there certainly is. 

Some sound-dampening material should cure that.  I recommend the foam pyramidal/tetrahedral panels a la anechoic chamber. 

                           Truly,
                           Robert Bernardo
                           Fresno Commodore User Group
                           http://videocam.net.au/fcug
                           The Other Group of Amigoids
                           http://www.calweb.com/~rabel1/

[bacon]

Unless you have a 128 DCR where both the C128 and C64 KERNALs are combined in one chip, you'll have to swap out both KERNALs if you want JiffyDOS functionality in C64 mode too.

[sirmorris]

Aha! That might explain some of this:

http://www.lemon64.com/forum/viewtopic.php?p=310430&sid=8be7f42e96bcb0d78e958117ab3cde92

I would like this to work primarily in '64 mode. so...

> Part number 251913-01 is the 16K 64 OS ROM, which is present in both the 64C
> and the low-profile 128.

Hmm. The '64 file in the Wiskow collection (huge thanks btw!) is only 8k.

Also, several sources note that this is the device I'll be replacing:


name:         HT23C128
function:     CMOS 16Kx8-Bit Mask ROM
package:      DIP/SOP28,28
manufacturer: Holtek

    +--()--+
NC | 1  28| VCC
A12 | 2  27| OE1/OE1B/NC
A7 | 3  26| A13
A6 | 4  25| A8
A5 | 5  24| A9
A4 | 6  23| A11
A3 | 7  22| OE/OEB/NC
A2 | 8  21| A10
A1 | 9  20| CE/CEB/OE2/OE2B
A0 |10  19| D7
D0 |11  18| D6
D1 |12  17| D5
D2 |13  16| D4
VSS |14  15| D3
    +------+

This pinout came from the Chipdir: http://www.chipdir.org/

And this looks to be pin compatible with the 27c128. Didn't someone say I needed to reroute a couple of pins? The chips in the pix from the Lemon site don't seem to be hacked, the

Sorry for all the dumbness, I'm just trying hard to make sense of what seems like contradictory data. My aim is to have a One-Tru-Place for all newbies to come and say - aha! That's the way

Thanks for your patience!

[sirmorris]

OK, I did some further digging and found enough to convince myself that the following will work for C128 mode:

* Burn JiffyDOS_C128.bin to a 27c128 eprom.
* Replace part #318020-03 with the eprom.
* Have joy.



Next - on to the '64 portion.

[Andrew Wiskow]

Please note that JiffyDOS ROMs are made available for educational purposes only. 

[RobertB]

...JiffyDOS ROMs are made available for educational purposes only. 

Hey, I qualify, because I am an educator! 

                       With the union card to prove it,
                       Robert Bernardo
                       Fresno Commodore User Group
                       http://videocam.net.au/fcug
                       The Other Group of Amigoids
                       http://www.calweb.com/~rabel1/

[sirmorris]

This is purely an educational experience for me too

Further digging led me to http://www.zimmers.net/anonftp/pub/cbm/firmware/computers/c64/ where I found rom dumps and information about various firmwares.

It looks like the '128 '64 rom contains basic and kernel. Binary comparison showed that basic.901226-01.bin and kernal.901227-03.bin are the versions which are combined into the '128 rom in that order. I might just read the ROM out of my machine just to make100% sure.

**update - roms read and verified identical to those found earlier.

I'll be burning the basic portion combined with an ever so educational jiffy kernel replacement (JiffyDOS_C64.bin) later today. Again I'll be using a 27c128, and dropping this into the machine in U32.

I'm really sorry if this is covered elsewhere, but if it is then I didn't find it

[Golan Klinger]

While you're at it you might as well burn something for your function ROM socket too.

[sirmorris]

I was thinking about that! It's a shame to leave that space empty

Any suggestions? The machine will mainly be in '64 mode.

[Golan Klinger]

The machine will mainly be in '64 mode.

Unfortunately it isn't of use in 64 mode. You've got a lot of choices in 128 mode though. If you're a GEOS user you could put GEOS in there and if you're into BASIC programming, BASIC 8 would be a good choice. I tend to lean towards utility ROMs like Servant or the 1581 Tools. I'm pretty sure there's a list of all the various option ROMs around here somewhere and I think dumps of those ROMs are floating around too. If not we should probably put something together. I'll look into it.

[airship]

Andrew has The Servant and KeyDOS ROMs on the same page as the JiffyDOS ROMs: http://cottonwood.servebbs.com/wiskow/

[got128]

   For my educational testing, I have installed The Servant with JiffyDos and they both work together quite well.

If you want to get fancy, you can burn a couple of images onto a 27C512 with a header and switch between the two.

There is a drawing of one on Ray Carlsen's website here:  http://staff.washington.edu/rrcc/uwweb/EPROM/2x256.gif

I have not cross-checked the pinouts, but it looks like it should work.

got128

[Andrew Wiskow]

  For my educational testing, I have installed The Servant with JiffyDos and they both work together quite well.

Yup!  On one C128, I even have both JiffyDOS and The Servant installed inside the C128, and KeyDOS installed in the Function ROM socket in the 1750 REU attached to it.  All three work quite well in harmony with one another. 

[airship]

That's pretty much the setup I want eventually, Andrew. I'm waiting for sockets right now.

I'll probably send my 1764 out for upgrading eventually and have a ROM socket installed at the same time.

My soldering skills aren't what they once were. I expected my eyes to be the problem by this age, but ironically I've had eye surgery and have the best vision of anyone I know. It's my hands that have given out, due to diabetic neuropathy. Life is full of surprises. Fortunately, you can still pay people money to do things like this for you. 

[Andrew Wiskow]

I'll probably send my 1764 out for upgrading eventually and have a ROM socket installed at the same time.

I'm not sure about the 1764, but in my 1750, in addition to installing the socket, I also had to cut a jumper and put another jumper in to get it to recognize the EPROM that I used for KeyDOS.  Here's the info that was posted to comp.sys.cbm that I used when I installed it:

The 1750 REU board is a bit different than the 1700 REU and does not
have the same jumpers. The 1750 REU is configured by default to use a
27128 EPROM with no modifications but the Servant EPROM I am using is
on a 27256.


To use a 27256 EPROM on a 1750 REU you have to cut the trace that is
already in place on J2, this is the 27128 position:


(back of 1750 REU)
   [ ]
    I  > For 27128 EPROM
J2 [ ]
       > For 27256 EPROM
   [ ]
(front of 1750 REU)


and then put a jumper from the front pad to the middle pad. Ta-da!
Working Servant EPROM on the 1750 REU!

[airship]

That much I can probably handle myself. Cutting a couple of traces and adding a jumper or two is no problem, but trying to solder to rows of .10" IC pads is.

[Andrew Wiskow]

That much I can probably handle myself. Cutting a couple of traces and adding a jumper or two is no problem, but trying to solder to rows of .10" IC pads is.

I understand...  Do you have someone in mind to do this for you locally?  If not, Charles Gutman of 8-Bit Deigns is the guy that soldered the socket on mine, and I'm sure he'd be happy to help you out, too.

[airship]

Yeah, Charles is the guy. I emailed him a couple of days back and am waiting for a response.