Burst mode for C64 mode

[Diddl]

I have found an article about burst mode for C64. Only two wires are nessecary from CIA to IEC port. Since I have some 1571 and one 1581 I tried this solution and it works perfectly.

Now I have found a burst kernel for C64 (cassette routines are lost). So my C64 works very fast with my burst drives, but 1541 is also working same time (slowly).

Now I got a C128-D with internal 1571 drive. C64 mode of this wonderful device is very slowly, so I tried to update kernel to this burst kernel.

It works very fine and it is very compatible (if 1571 run slowly, it will run also fast in burst mode). So it is a very good solution for me.

You will need a special adapter cause original kernel has a 23128 PIN layout. Replacement eproms like the 27128 have a different PIN layout: see here

[BigDumbDinosaur]

You will need a special adapter cause original kernel has a 23128 PIN layout. Replacement eproms like the 27128 have a different PIN layout: see here

Commodore was always good about using hinky silicon that couldn't be readily replaced by JEDEC standard parts. 

[marquisor]

As I got a C128DCR, too that's an interesting issue for me...

Am I right if I say the hardware modification has to be ALWAYS DONE?
...and in addition a new KERNAL for C64 mode is MANDATORY?

Or does it just work with a hardware mod, as C128DCR already got the right KERNAL?! Even resp. esp. for C64 mode...

Next possible configuration comes in my mind is that the C64 mode has its own KERNAL and the C128 mode its own KERNAL, so TWO ROM chips sit on the C128DCR mainboard?

Please bring light into (my) darkness Thx

Regards
marquisor


PS: Is there a software solution for getting burst transfer speeds in C64 mode? For doublesided disks I use "U0>M1", but no burst speedup then...

[bacon]

You will need a special adapter cause original kernel has a 23128 PIN layout. Replacement eproms like the 27128 have a different PIN layout: see here

This article from Cameron Kaiser's Commodore Knowledge Base (originally from Usenet) describes how to make a simple modification to a C128 so it will accept standard 27256 EPROM chips. I did this years ago with my C128 and I can testify that it's very easy to do.

[Diddl]

Or does it just work with a hardware mod, as C128DCR already got the right KERNAL?! Even resp. esp. for C64 mode...

First I was thinking it works without a hardware mod only by replacing C64 kernel.

But now I got another C128-D from a friend and my modified kernel doesn't work for him (only slow speed).

So it seems to be sure, an additional hardware mod must be done like on a normal C64. C128 in C64 mode seems to have problems to use burst hardware.

Next possible configuration comes in my mind is that the C64 mode has its own KERNAL and the C128 mode its own KERNAL, so TWO ROM chips sit on the C128DCR mainboard?

Yes of course! C128 has 2 kernels, one for C128 mode and one for C64 mode.

PS: Is there a software solution for getting burst transfer speeds in C64 mode? For doublesided disks I use "U0>M1", but no burst speedup then...

With this special kernel +  hardware mod (wire to SRQ) you don't need this command. Burstmode automatically is used if a burst able drive is connected. It works same as in C128 mode.