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Majikeyric
Registered: Sep 2002
Posts: 83 |
How does linecrunch work ?
Hi everybody !!!!
Can someone explain or point me to a web site where I could find information about linecrunch ???
I think it allows to scroll bitmaps but I don't know how ???
thanks. |
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Ninja
Registered: Jan 2002
Posts: 404 |
a c64 that cannot do FLI? Wooow, wanna have, ULTRA-RARE, big bucks on ebay!! ;)) |
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algorithm
Registered: May 2002
Posts: 702 |
It might be a power supply problem. I know it sounds very unusual.
All demo's and games which shift the screen horizontally using a graphic trick (placing specific byte combinations in $d011 followed by a self modified delay and yet another value in $d011) would seem to randomly crash the entire system.
During my C64 days (A very long time ago) I had created a small utility which would test this and give a report on the amount of bytes that were corrupted. If it did this or crashed (Due to the very possible corruption of program data) I would find that switching the system off and on would sometime solve the problem.
Mind you, this would sometimes have to be done 7 or 8 times.
After a while, I got a new power supply unit and guess what. This problem never happened again!!
I had previously read somewhere that the the linecrunch routine causes the VICII chip to draw in more power and a faulty or weak powersupply would cause memory corruption. Who knows...
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Shadow
Account closed
Registered: Apr 2002
Posts: 355 |
I have this problem with my C64 (new model, not the breadbox).
Many demos that have graphic scrolling lock up after just a few seconds. Never had any issues with games though, and FLI etc. works perfectly. |
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
"new model" doesn't mean anything except for the casing. it most likely still has an old board inside with 65xx ic's. |
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raven
Account closed
Registered: Jan 2002
Posts: 137 |
well none of my machines have this problem (old,new,flat 128, 128D) but i've seen it happen on one machine (c64c) at X2001..
Thats one very interesting problem |
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Cybernator
Registered: Jun 2002
Posts: 154 |
I've tested all my C64s, and the only thing that doesn't work on old ones, is $DE00 programs.
One of my new C64s works fine, except with Insomnia (of course there must be something else, but this is what I have found so far). The computer simply locks up at the beginning. I suspect that CIA2 is blown. One old C64, gives me a message saying something like: "Disk drive not present", although it works with other programs as well.
@Raven: What does your code do at the beginning? (Before the screen fader). I guess it installs the fastloader into the 1541s memory. So most probably it's CIA2. But strange thing is that everything else I've tried so far, works perfect.
@Graham: Btw, on your site I've read that the 8500 is 6510 with different pin layout. I haven't tried to swap the processors, but I've seen an old C64 with 8500 processor (it didn't seemed to be resoldered at home). It worked normally. Are you sure it's the pin layout? I assumed it was the voltage difference here.
Btw, anyone knows the difference between 6526-A (used in new C64s), and 6526 (used in old C64s)? |
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Stryyker
Registered: Dec 2001
Posts: 465 |
I think the A means 2MHz mode available too. |
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yago
Registered: May 2002
Posts: 332 |
Concerning different CIAs:
There is a way of detecting them, one type needs longer for an IRQ (mist's diag-prg did this)
I also discovered memory-faintings when fidling with D011 on a "all-new" c64, and concluded that this does only happen when the c64 is not switched on a long time.
Don't know if this due to power-supply or other things..
Murphys Law regarding linecrunching:
It works on all machines, except on the organizers one.
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Cybernator
Registered: Jun 2002
Posts: 154 |
Stryyker wrote:
"I think the A means 2MHz mode available too."
I understand using this chip in C128, but why would someone use it in a C64C ??? I've even seen CIAs like "6526A-1" and "6526B". What teh heck does this mean? :/
Yago wrote:
"Concerning different CIAs:
There is a way of detecting them, one type needs longer for an IRQ (mist's diag-prg did this)"
You mean the IRQ occurence is delayed? (In case I understood you right). I just made a little test-routine which uses double raster interrupt to stabilize, and then starts timer A of CIA1, which then generates interrupt and changes the border color. (DEN is set to 0, btw).
Then I've used both version of CIA, and the color change happened exactly at the same place.
I've probably misunderstood ya. Where can I find the routine you mentioned?
Yago wrote:
"I also discovered memory-faintings when fidling with D011 on a "all-new" c64, and concluded that this does only happen when the c64 is not switched on a long time.
Don't know if this due to power-supply or other things.."
Ok, I realize my English sux :P Do you mean the C64 was NEW-VERSION, or it was new (NOT RAPED)? :) Or maybe all NEW-VERSION _C64s_ you have tried?
Never noticed such a problem. Only that those grey dots (when changing border/paper color) may appear or disappear when switching the C64 on/off.
Yago wrote:
"Murphys Law regarding linecrunching:
It works on all machines, except on the organizers one."
Hehe :-) |
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yago
Registered: May 2002
Posts: 332 |
To recognize the both CIAs (6526 & 8???), try the Program "diag" which might be found here:
http://www.weihenstephan.org/~michaste/mxass/
If it not included inside the Assembler anymore, contact me.
My "new C64" has all new Chips, SID, VIC, everything.
It has also a green LED, and msmakelas shiftlock-detection does not work as reliable as on other C64s (which seems to be an attribute of the mainboard/cia, NOT the keyboard).
I have also other "new version" c64 (to be honest, I use only non-breadbox-c64), but most of them have "old" chips.
The "dot"-problem can be used to manually detect a new VIC.
lda #0
sta $d011
loop: sta $d020
jmp loop
PS: "old" chips = 6xxx
"new" chips = 8xxx
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