Epson Research and Development
Page 111
Vancouver Design Center
Hardware Functional Specification
S1D13505
Issue Date: 01/02/02
X23A-A-001-14
bit 3
LCD Power Disable
This bit is used to override the panel on/off sequencing logic.
When this bit = 0 the LCDPWR output is controlled by the panel on/off sequencing logic.
When this bit = 1 the LCDPWR output is directly forced to the off state.
The LCDPWR “On/Off” polarity is configured by MD10 at the rising edge of RESET# (MD10 = 0
configures LCDPWR = 0 as the Off state; MD10 = 1 configures LCDPWR = 1 as the Off state).
bits 2-1
Suspend Refresh Select Bits [1:0]
These bits specify the type of DRAM refresh to use in Suspend mode.
Note
These bits should not be changed while suspend mode is active.
bit 0
Software Suspend Mode Enable
When this bit = 1 software Suspend mode is enabled.
When this bit = 0 software Suspend mode is disabled.
See Section 15 Power Save Modes for details.
8.2.7 Miscellaneous Registers
bit 7
Host Interface Disable
This bit is set to 1 during power-on/reset.
This bit must be programmed to 0 to enable the Host Interface. When this bit is high, all memory
and all registers except REG[1Ah] (read-only) and REG[1Bh] are inaccessible.
bit 0
Half Frame Buffer Disable
This bit is used to disable the Half Frame Buffer.
When this bit = 1, the Half Frame Buffer is disabled.
When this bit = 0, the Half Frame Buffer is enabled.
When a single panel is selected, the Half Frame Buffer is automatically disabled and this bit has no
effect.
The half frame buffer is needed to fully support dual panels. Disabling the Half Frame Buffer
reduces memory bandwidth requirements and increases the supportable pixel clock frequency, but
results in reduced contrast on the LCD panel (the duty cycle of the LCD is halved). This mode is
not normally used except under special circumstances such as simultaneous display on a CRT and
dual panel LCD. When this mode is used the Alternate Frame Rate Modulation scheme should be
used (see REG[31h]). For details on Frame Rate calculation see Section 14.2, “Frame Rate Calcu-
lation” on page 141.
Table 8-10: Suspend Refresh Selection
Suspend Refresh Select Bits [1:0]
DRAM Refresh Type
00
CAS-before-RAS (CBR) refresh
01
Self-Refresh
1X
No Refresh
Miscellaneous Register
REG[1Bh]
RW
Host Interface
Disable
n/a
n/a
n/a
n/a
n/a
n/a
Half Frame
Buffer Disable