Product specifications

VT8601A Apollo PLE133
Revision 1.82 October 22, 2001 -85- VGA Extended Registers
Technologies, Inc.
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Power Management Registers
GR20 – Standby Timer Control........................................RW
7 Timer Initialize & Enable
0 Enable Timer.......................................... default
1 Initialize and hold standby and DPMS timer
6-4 Timer Testing ....................................................... RO
3-0 Reserved .........................................always reads 0
GR21 – Power Management Control 1............................RW
7 Power Management Pin Polarity
0 Active High............................................ default
1 Active Low
6 PCI Power Management
0 Disable ................................................... default
1 Enable
5 Suspend Mode
0 Normal mode.......................................... default
1 Enter Suspend Mode
4 Suspend Input Pin
0 Disable ................................................... default
1 Enable
3 D3 to D0 Reset
0 Disable ................................................... default
1 Enable
2 Standby Input Pin
0 Disable ................................................... default
1 Enable
1 CLKRUN# Mechanism
0 Disable ................................................... default
1 Enable
0 Consistent Standby / Suspend
0 The bits in the PCI PM configuration registers
will be OR’ed with bits 5 and 3 of this register
for connection to the internal PM state
machine .................................................. default
1 The bits in the PCI PM configuration registers
will be the same as bits 5 and 3 of this register
to allow software coherency
GR22 – Power Management Control 2............................RW
7 Timer Test Mode
0 Disable ....................................................default
1 Enable
6 Refresh Clock Select
0 Crystal input or external clock (XMCLK)
provides refresh clock during suspend ...default
1 REFCLK is used as refresh clock during
suspend for 64ms refresh (ignore “Suspend
DRAM Refresh Mode” bits 5-4 below)
5-4 Suspend DRAM Refresh Mode
00 No refresh ...............................................default
01 Self refresh
10 Crystal clock provides rate for 8ms refresh
11 Crystal clock provides rate for 64ms refresh
3 Disable GPIO
0 Allow GPIO 7-0 pins to drive data in.....default
1 Disable GPIO 7-0 pins (and their shared
functions) from driving data. Tristates input
buffers on pins so no power is consumed if
GPIO pins are set to input mode.
2 Reserved ......................................... always reads 0
1 Hardware / Software Oscillator Select
0 Software controls oscillator off with bit-0
(prevents automatic oscillator shutdown
without direct software control of the
“Oscillator Disable” bit) ...............................def
1 Hardware controls oscillator off (allow
oscillator shutdown when power states are
entered using hardware mechanisms)
0 Oscillator Disable
0 Enable normal function ..........................default
1 Disable (oscillator off)