Re: VIC-1541 problem

From: Pasi Ojala (
Date: 2006-12-22 19:40:57

> This gives me one question: Does this same error occur if a 1541 (in C64
> mode) is attached to a VIC 20?

I just tested the VIC20 machine language monitor with 1581 and the
save command seems to work fine. However, I have replaced the 1581
ROM in the meantime, so my recollection can still be correct.

Around 1989 Jussi Salo run a BBS with a VIC20 and had to return
his 1581 drive because it did not work reliably. I don't
know/remember anymore what the problems were.

But I checked the Veni Vidi Vici! loader code at least.
When the drive code is M-W:ed to the drive:
- the 1541 version has 3 NOP's after jsr ciout (or are these my own additions?)
- for the 1581 version a much larger delay was required (about 250 cycles)
  to make it work.
- but now it works without the delay (in VICE) just fine.

So, please forget everything I said previously. It is just hear-say until
I can come across _any_ problems with vic20 and 1581 again.

Perhaps I have to revert my 1581 to a previous revision to check this thing.

"That's all that faith requires. That we surrender ourselves to
 the possibility of hope. For that I'm content."
	-- Brother Alwyn in Babylon 5:"The Deconstruction of Falling Stars"

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