Epson S1D13504 ユーザーズマニュアル
Page 30
Epson Research and Development
Vancouver Design Center
S1D13504
Programming Notes and Examples
X19A-G-002-07
Issue Date: 01/02/01
5 LCD Power Sequencing and Power Save Modes
5.1 Introduction to LCD Power Sequencing
LCD Power Sequencing allows the LCD power supply to discharge prior to shutting down the LCD
signals. Power sequencing is required to prevent long term damage to the panel and to avoid
unsightly “lines” on power down and start-up.
signals. Power sequencing is required to prevent long term damage to the panel and to avoid
unsightly “lines” on power down and start-up.
LCD Power Sequencing is performed on the S1D13504 through a software procedure even when
using hardware power save modes. Most “green” systems today use some sort of software power
down procedure in conjunction with external circuitry to set hardware suspend modes. These proce-
dures typically save/restore state information, or provide a timer prior to initiating power down. The
S1D13504 requires a timer between the time the LCD power is disabled and the time the LCD
signals are shut down. Conversely, the LCD signals must be active prior to the power supply starting
up. For simplicity, we have chosen to use the same time value for power up and power down proce-
dures.
using hardware power save modes. Most “green” systems today use some sort of software power
down procedure in conjunction with external circuitry to set hardware suspend modes. These proce-
dures typically save/restore state information, or provide a timer prior to initiating power down. The
S1D13504 requires a timer between the time the LCD power is disabled and the time the LCD
signals are shut down. Conversely, the LCD signals must be active prior to the power supply starting
up. For simplicity, we have chosen to use the same time value for power up and power down proce-
dures.
The time interval required varies depending on the power supply design. The power supply on the
S5U13504B00C Evaluation board requires 0.5 seconds to fully discharge. Your power supply
design may vary.
S5U13504B00C Evaluation board requires 0.5 seconds to fully discharge. Your power supply
design may vary.
Below are the procedures for all cases in which power sequencing is required.
5.2 Introduction to Power Save Modes
The S1D13504 has two power save modes. One is hardware-initiated via the SUSPEND# pin, the
other is software-initiated through REG[1A] bit 0. Both require power sequencing as described
above.
other is software-initiated through REG[1A] bit 0. Both require power sequencing as described
above.
5.3 Registers
Register bits discussed in this section are highlighted.
Suspend Refresh Select bits [1:0] should be set on power up depending on the type of DRAM
available. See the Hardware Functional Specification, document number X19A-A-002-xx.
available. See the Hardware Functional Specification, document number X19A-A-002-xx.
Display Mode Register
REG[0D]
REG[0D]
n/a
Simultaneous
Display
Option Select
Bit 1
Display
Option Select
Bit 1
Simultaneous
Display
Option Select
Bit 0
Display
Option Select
Bit 0
Number of
BPP Select
Bit 2
BPP Select
Bit 2
Number of
BPP Select
Bit 1
BPP Select
Bit 1
Number of
BPP Select
Bit 0
BPP Select
Bit 0
CRT Enable
LCD Enable
Power Save Configuration Register
REG[1A]
REG[1A]
n/a
n/a
n/a
n/a
LCD Power
Disable
Disable
Suspend
Refresh
Select Bit 1
Refresh
Select Bit 1
Suspend
Refresh
Select Bit 0
Refresh
Select Bit 0
Software
Suspend
Mode Enable
Suspend
Mode Enable