Compaq 4000N - Manual (Page 133)

Technical Reference Guide
Compaq Deskpro 4000N and 4000S Personal Computers
First Edition - September 1997
6-5
Table 6–5. S3-Specific Control Register Mapping
Table 6-5.
S3-Specific Control Register Mapping
I/O
Address
Function
I/O
Address
Function
3x5.2D..3Ch [1] Extended VGA Registers 42E8h, 4AE8h Enhanced Command Registers
3x5.40..4Fh [1] Control Registers 8180h-81FCh Streams Processor Registers
3x5.50..6Fh [1] Extension Registers 82E8h-E2EAh Enhanced Command Registers [2]
-- -- FF00h-FF40h Local Peripheral Bus Registers
x = B, Monochrome
x = C, Color
[1] Index at 3x4h
[2] Addresses not contiguously used through range.
6.2.4 MONITOR POWER CONTROL
This system provides monitor power control for monitors that conform to the VESA display
power management signaling protocol. This protocol defines different power consumption
conditions and uses the HSYNC and VSYNC signals to select a monitor’s power condition.
Table 6-6 lists the monitor power conditions.
Table 6–6. Monitor Power Management Conditions
Table 6-6.
Monitor Power Management Conditions
HSYNC VSYNC Power Mode Description
Active Active On Monitor is completely powered up. If activated, the inactivity
counter counts down during system inactivity and if allowed to
tiemout, generates an SMI to initiate the Suspend mode.
Active Inactive Suspend Monitor’s high voltage section is turned off and CRT heater
(filament) voltage is reduced from 6.6 to 4.4 VDC. The Off mode
inactivity timer counts down from the preset value and if allowed to
timeout, another SMI is generated and serviced, resulting in the
monitor being placed into the Off mode. Wake up from Suspend
mode is typically a few seconds.
Inactive Inactive Off Monitor’s high voltage section and heater circuitry is turned off.
Wake up from Off mode is a little longer than from Suspend.
The timeout parameter set in the SIT record 03h and indexed at CMOS location 2Ch (bits
<4..0>) represents the period of system I/O inactivity required to elapse before the monitor is
placed into Suspend mode.
A separate timer function (enabled through CMOS location 1Fh, bit <1>) can be enabled to place
the monitor into the Off mode after 45 minutes of being in Suspend mode.