VT8601 Via, VT8601 Datasheet - Page 94

• Manufacturer Part Number: VT8601
• Description: Slot-1 / Socket-370 PCI North Bridge
• Manufacturer: Via

GR26 – DPMS Control ..................................................... RW
Revision 1.3 September 8, 1999
7-6
5-4
2-0
3
7HFKQRORJLHV ,QF
RAMDAC Internal Power Control
Reserved
DPMS Control
Reserved
:H &
:H &R R QQHFW
00 Normal ...................................................default
01 DAC off (used in LCD only mode)
10 Standby (DAC off, LUT in low power mode,
11 Suspend (DAC off, LUT access disallowed
0
1
QQHFW
I/O allowed to LUT). May be used in LUT
bypass mode.
but LUT contents are preserved)
Software Control Mode: DPMS controlled by
GR23[1-0] in simultaneous display and CRT-
only modes (may be used to decouple the
power modes of the CRT and LCD during
simultaneous display) ..........................default
Hardware Control Mode: DPMS controlled
by internal power states.
........................................ always reads 0
........................................ always reads 0
-88
DPMS Control Modes
DPMS Software Control Mode
In simultaneous display mode, the software control mode can
be used to control DPMS low power states independent of the
chip power states. In CRT display mode, software mode
gives total DPMS control to software. Pseudo-standby may
be controlled by bits 7 and 6, as well as BLANK# timing.
DPMS Hardware Control Mode
DPMS hardware timer mode is defined as CRT only mode
with the DPMS control mode bit set to hardware (bit 3 =1).
Activity detection is set by register GR21[2:0]. Status is
indicated in bits 1 and 0. The timer may be controlled by
software from GR20[7].
Table 9. DPMS Sequence - Hardware Timer Mode
Table 10. DPMS Sequence - Hardware Mode in
In simultaneous display mode with hardware DPMS
set, DPMS states are sequenced by the timer, pin, and
register bits that control the chip power states.
Moderate - 16 min inactivity
Lowest - 64 min inactivity
High - Activity detected
Moderate - Chip standby
Low - 32 min inactivity
Lowest - Chip off state
High - Chip on state
Low - Chip suspend
Simultaneous Display Mode
Power Level
Power Level
VT8601 Apollo ProMedia
VGA Extended Registers
DPMS Mode
DPMS Mode
Suspend
Standby
Off
Off
Off
Off
On
On