Power Save Modes; Table 15-1: Power Save Mode Function Summary; Table 15-2: Pin States In Power-Save Modes - Epson S1D13505 Technical Manual

Epson Research and Development
Vancouver Design Center

15 Power Save Modes

Function
Display Active?
Register Access Possible?
Memory Access Possible?
LUT Access Possible?
Pins
LCD outputs
LCDPWR
DRAM outputs
CRT/DAC outputs
Host Interface outputs
Hardware Functional Specification
Issue Date: 01/02/02
Three power save modes are incorporated into the S1D13505 to meet the important need for power
reduction in the hand-held device market.

Table 15-1: Power Save Mode Function Summary

Normal
(Active)

Table 15-2: Pin States in Power-save Modes

Normal
(Active)
Active
(LCDEnable = 1)
On
(LCDEnable = 1)
Active
Active
(CRTEnable = 1)
Active
1. Refresh method is selectable by REG[1Ah]. Supported methods are CBR refresh, self-refresh
or no refresh at all.
2. The FPFRAME and FPLINE signals are set to their inactive states during power-down. The in-
active states are determined by REG[07h] bit 6 and REG[0Ch] bit 6. A problem may occur if
the inactive state is high (typical TFT/D-TFD configuration) and power is removed from the
LCD panel.
For software suspend the problem can be solved in the following manner. At power-down, first
enable software suspend, then wait ~120 VNDP, and lastly reverse the polarity bits. At power-
up, first disable software suspend, then revert the polarity bits back to the configuration state.
For hardware suspend an external hardware solution would be to use an AND gate on the sync
signal. One input of the AND gate is connected to a sync signal, the other input would be tied
to the panel's logic power supply. When the panel's logic power supply is removed, the sync
signal is forced low.
Power Save Mode (PSM)
No Display
LCDEnable = 0
CRTEnable = 0
Yes No
Yes Yes
Yes Yes
Yes Yes
Pin State
No Display
LCDEnable = 0
CRTEnable = 0
2
Forced Low
Off
CBR Refresh
only
Disabled
Active
Software Hardware
Suspend Suspend
No
Yes
No
Yes
Software Hardware
Suspend Suspend
2
Forced Low Forced Low
Off Off
1
Refresh Only Refresh Only
Disabled Disabled
Active Disabled
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No
No
No
No
2
1
S1D13505
X23A-A-001-14