 Previous Messages |
Posted By
Chicken
on 2016-03-01
17:22:46
 |  Re: PROJECT 64?
Hi SVS,
just to confirm and clarify what's been said before …
"Project64" is not only a Nintendo N64 emulator but also a CBM knowledge base. There's a document on plus/4 there which includes the erroneous $ff07 description (taken from the source mentioned by JamesC):
http://project64.c64.org/hw/plus4maps.txt
Scroll down to "Graphics Chip Register Map"
… and you'll find this:
"$FF07 65287 …
5 Flashing: 0 = yes, 1 = no"
gerliczer linked to a document which is based on various sources – one of them is "Project64". Since the information is contradictory to what other sources say, both descriptions for that bit are mentioned.
There's a similar situation for $ff11 in that document:
"Bit0-3 Volume. Maximum value is 8. //OR:// 0=Off, F=Highest"
Anyway, "PROJECT64" just refers to the "PROJECT64" documentation. It's not some magic hardware 
Back to the FREEZE bit … In the description it says
"TED stop. If set, the TED stops it's counters and screen-generating, only single clock and refresh cycles remain."
I'm not 100% sure about the refresh cycles because I experienced (if I recall correctly) something different, i. e. memory corruption. Can anybody confirm this on real hardware?
|
|
Posted By
SVS
on 2016-03-02
02:52:38
 | Re: PROJECT 64?
Yes me too I'm sure this bit causes TED freezing.
I was asking about that "Project 64" supposing it was a ghost/magic hardware mod )
Then do you confirm it was only a documentation taken from the Reference Guide?
|
|
Posted By
Chicken
on 2016-03-01
03:09:24
| Re: PROJECT 64?
It's definitely the FREEZE bit. I guess almost everybody interested in TED and demos has wondered about this bit and played around with it hoping to discover some magic trick Setting it is for instance a slow way to clear (or rather corrupt?) RAM.
Have to admit that I've never checked this in any of the emulators.
|
|
Posted By
JamesC
on 2016-02-29
14:41:54
| Re: PROJECT 64?
Ha. Now that I see what we're talking about, I agree with gerliczer.
Project64's TED data is a direct copy from the Plus/4 Programmers Reference Guide, page 423. Bit 5 of $FF07 is documented as a "flashing" bit. But looking at the TED System Technical Data Document, page 35, this is the "freeze" bit.
Playing around with YAPE seems to verify that bit 5 is really a freeze bit -- turning it on causes a black screen and the system seems to lock up.
The Programmers Reference Guide is clearly incorrect.
|
|
Posted By
gerliczer
on 2016-02-29
13:50:51
| Re: PROJECT 64?
Are you talking about this document, SVS? I think that only meant to mark that the documentation at Project 64 site is erroneous.
|
|
Posted By
JamesC
on 2016-02-29
14:47:35
| Re: PROJECT 64?
(Post cleared by JamesC, now that it's clear which document is being discussed. :) )
|
|
Posted By
SVS
on 2016-02-29
08:58:50
| PROJECT 64?
Who knows something about this? I've found on a document that bit 5 of TED Register 07 could be used as Flashing flag for "PROJECT 64".
Normally the same bit can halt all the TED counters.
|
|
