SPC8106 S-MOS Systems, SPC8106 Datasheet - Page 113

• Manufacturer Part Number: SPC8106
• Description: LCD/CRT VGA CONTROLLER
• Manufacturer: S-MOS Systems

9.0
9.1
To accommodate the important need for power reduction in sub-notebook and palmtop comput-
ers, one hardware controlled and five software controlled Power Save Modes have been incorpo-
rated into the SPC8106. Options for these Power Save Modes can be enabled by setting bits in
various Auxiliary registers, allowing flexibility in tailoring of the power reduction scheme to any
given system implementation.
Software Power Save Modes
The Power Save Mode bits in the Power Save Register, AUX[03], select one of the six software
Power Save Modes as shown in the table below. Note that if hardware Suspend mode is acti-
vated, the software power save mode setting in this register is ignored (i.e. hardware Suspend
mode overrides the software power save modes). If these bits are set to a values 110b or 111b,
then the chip will remain in normal active mode. The following descriptions outline the major func-
tions of each power save mode. Some differences in power save mode operation exist between
LCD and CRT display modes - see the following tables and notes for more information.
SPC8106
Software Power Save Mode 1
•
•
•
•
•
•
•
411-1.0
No video display accesses to display memory.
Sequencer is dedicated to CPU accesses to/from display memory.
Display memory refresh is maintained and is generated from active CLKI input (28 MHz for LCD, 25 MHz or
28 MHz for CRT). Refresh rate can be selected: 64 kHz or 8 kHz, (for 256 cycle/4 ms, or 256 cycle/32 ms
DRAM, respectively).
I/O read/write of all registers is allowed.
LCDPWR# and IREFEN# signals forced high.
LCD and TFT interface output signals tri-stated or forced low, depending on the state of the LCD Signal PS
Mode bit in LCD Support Register 1, AUX[02] bit 1.
If CRT display enabled, CRT and RAMDAC interface signals forced low (except DACRD# and DACWR#
which remain active).
POWER SAVE MODES
Power Save Modes
Power Save Mode Select
bit 2
0
0
0
0
1
1
1
S-MOS Systems, Inc. • Tel: [phone] • Fax: [phone] • http://www.smos.com
bit 1
0
0
1
1
0
0
1
bit 0
Table 0-42 Software Power Save Modes
0
1
0
1
0
1
0
Normal Operation
Power Save Mode 1 enable
Power Save Mode 2 enable
(toggle between states 1 & 2, see below)
Power Save Mode 3 enable
Power Save Mode 4 enable
Power Save Mode 5 enable (n/a for CRT mode)
Power Save Mode 6 enable (n/a for CRT mode)
X12-SP-001-07
Mode Activated
Hardware Functional Specification
SP1-71