Intel 815 Manuel D’Utilisation

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Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0 
 
 
 
R
 
140  
 
9.6.40. CR81
Reserved 
I/O (and Memory Offset) Address:  3B5h/3D5h(index 81h) 
Default: 00h 
Attributes Read/Write 
This register is not present in 2D. 
 
 
 
 
 
 
 
Reserved (00000000) 
 
Bit Description 
7:0 
Reserved. (This register did something useful in ‘554, and was not completely removed from Portola 
database, even though it does nothing useful). 
9.6.41. CR82
Blink Rate Control 
I/O (and Memory Offset) Address:  3B5h/3D5h(index 82h) 
Default: 00h 
Default:  
83h is the VGA default, but 88h is used instead because 
that’s a more visually  
appealing value 
Attributes Read/Write 
The h/w default for this register does not match the VGA compatibility requirements. BIOS must make 
sure to set this register to correct value. 
 
7 6 
5     
Character Blink Duty 
Cycle 
VSync Blink Rate 
 
Bit Description 
7:6 
Character Blink Duty Cycle. (Character Blink is also known as Attribute Blink). 
00 = 50% duty cycle. 
01 = 25% duty cycle. 
10 = 50% duty cycle (power on default). 
5:0 
VSync Blink Rate. Controls the cursor blink rate in terms of the number of VSyncs on the following 
basis: the programmed value must be the (actual value/2)-1. (The default is 3).