23 lCD DRiVeR (lCD)
23-16
Seiko epson Corporation
S1C17624/604/622/602/621 TeChniCal Manual
Selects which of the two display areas reserved in the display memory is displayed when driving the
LCD in 1/4, 1/3, 1/2 duty or static drive. Setting DSPAR to 0 selects display area 0; setting to 1 selects
display area 1. See Figures 23.5.1 to 23.5.10 for the display areas.
D4
DSPReV: Reverse Display Control Bit
Inverts (negative display) the LCD display.
1 (R/W): Normal display (default)
0 (R/W): Inverted display
Setting DSPREV to 0 inverts the LCD panel display; setting to 1 returns the display to normal status.
This operation does not affect the contents of the display memory.
D[3:2]
Reserved
D[1:0]
DSPC[1:0]: lCD Display Control Bits
Controls the LCD display.
8.3 LCD Display Control
Table 23.
DSPC[1:0]
lCD display
0x3
All off (static)
0x2
All on (dynamic)
0x1
Normal display
0x0
Display off
(Default: 0x0)
For normal display, set DSPC[1:0] to 0x1. Note that the clock must be supplied. (See Section 23.3.)
If “Display off” is selected, the drive voltage supplied from the LCD system voltage regulator stops,
and the V
C1
to V
C3
pins are all set to V
SS
level.
Since “All on” and “All off” directly control the driving waveform output by the LCD driver, display
memory data is not altered. COM pins are set to dynamic drive for “All on” and to static drive for “All
off.” This function can be used to make the display flash on and off without altering the display memo-
ry.
DSPC[1:0] is reset to 0x0 (Display off) after an initial reset. DSPC[1:0] is also reset to 0x0 when the
slp
instruction is executed and it reverts to the previous setting after SLEEP mode is canceled.
lCD Contrast adjustment Register (lCD_CaDJ)
Register name address
Bit
name
Function
Setting
init. R/W
Remarks
lCD Contrast
adjustment
Register
(lCD_CaDJ)
0x50a1
(8 bits)
D7–4 –
reserved
–
–
–
0 when being read.
D3–0 lC[3:0]
LCD contrast adjustment
LC[3:0]
Display
0x7 R/W
0xf
:
0x0
Dark
:
Light
D[7:4]
Reserved
D[3:0]
lC[3:0]: lCD Contrast adjustment Bits
Adjusts the LCD contrast by controlling voltages V
C1
to V
C3
output by the internal LCD system voltage
regulator.
8.4 LCD Contrast Adjustment
Table 23.
lC[3:0]
Contrast
0xf
High (dark)
0xe
↑
:
:
0x1
↓
0x0
Low (light)
(Default: 0x7)
LC[3:0] is set to 0x7 after an initial reset. Initialization via software is required to achieve the required
contrast.