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From: fredriks@austin.ibm.com (Lars Fredriksen)
Subject: 800x600 mode with NEC GS2A and ATI Integra
Originator: @worf.cet.austin.ibm.com
Sender: news@austin.ibm.com (News id)
Message-ID: <C3p24s.140I@austin.ibm.com>
Date: Wed, 10 Mar 1993 22:22:04 GMT
Organization: IBM Austin
Keywords: XFree86, NEC, ATI
Lines: 130
Hi,
I am having slight difficulties trying to get the combination
of ATI Integra and NEC GS2A to work in 800x600 mode with XFree86 1.2.
Based on the numbers I got from NEC the following mode line should work.
"800x600" 36 800 824 896 1024 600 601 603 625
The NEC GS2A can use 31.5k and 35.2k hz horizontal frequency. It can handle
56/60/70 refresh rates.
+----------------+
_____| Video |_______
|<C>|<---------D---->|<E>|
__+ +________________________+ +_____
| | Sync | |
+---+ +---+
|<B>|
|<--------------A---------->|
Horizontal Freq: 35.2kHz
Vertical Lines: 600
A us 28.44
B us 2.0
C us 3.56
D us 22.22
E us 0.67
>From the above spec and drawing I concluded that:
Horizontal Guard before sync = E (24 clock ticks -> 824-800)
Horizontal Guard after sync = C (129 clock ticks -> 1024-896)
Horizontal sync pulse = B ( 72 clock ticks -> 896-824)
Visual = D ( 800 clock ticks -> 800)
Total = A (1024 clock ticks -> 1024)
Simularly for vertical:
+----------------+
_____| Video |_______
|<C>|<---------D---->|<E>|
__+ +________________________+ +_____
| | Sync | |
+---+ +---+
|<B>|
|<--------------A---------->|
Horizontal Freq: 35.2kHz
Vertical Lines: 600
A ms 17.78
B ms 0.06
C ms 0.53
D ms 17.07
E ms 0.03
>From this I got:
600 601 603 625
Well, it doesn't work at all. If I push 1024 to 1056 or so, I get something
that I at least can look at and see something. The screen looks as follows
+-----------------------+
| | | |
| 1 | 2 | 3 |
| | | |
|XXXXXXXXXXXXXXXXXXXXXXX|
| | | |
| 4 | 5 | 6 |
| | | |
|XXXXXXXXXXXXXXXXXXXXXXX|
| |
+-----------------------+
Where 1,2,3,4,5 and 6 are all a pease of the upper left hand corner of the
X root window. That is you see part of the login window here.
Obviously I am doing something wrong with my calculations or with my assumptions!
Could someone that have some experience with this sort of thing (or have the
same combo working) please tell me what I am doing wrong, or what direction
I should persue in order to get this to work.
Currently it is running fine with the following mode:
"640x480" 30 640 712 752 832 480 489 492 520
These number basically all means that the XFree86 is driving all the signals
faster than what NEC specifies:
Horizontal Freq: 31.5kHz
Vertical Lines: 480
Timing section: NEC XFree86
A us 31.78 27.7
B us 3.81 1.33
C us 1.91 2.4 *
D us 26.42 20.0
E us 0.64 2.6 *
The above is for horizontal Line. The entries marked with a * are the only
ones that are above the ones specified by NEC, all others are below.
I really appreciate any info that might help the situation (bying a new monitor
and controller is in the plans for this fall :-))
Thanks a lot,
Sincerely,
Lars Fredriksen
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