Lcd Bias Cont�Ol - Holtek BS82B12A-3 Manual

A cyclic LCD waveform includes two frames, known as Frame 0 and Frame 1 for which the
following offers a functional explanation.
In Frame 0
To select Frame 0 clear the FRAME bit to 0.
In frame 0, the COM signal output can have a value of V
SEG signal can have a value of V
In Frame 1
In frame 1, the COM signal output can have a value of V
SEG signal can have a value of V
The COM0~COMn waveform is controlled by the application program using the FRAME bit, and the
corresponding I/O data register for the respective COM pin to determine whether the COM0~COMn
output has a value of either V
way using the FRAME bit and the corresponding I/O data register for the respective SEG pin to
determine whether the SEG0~SEGn output has a value of either V
LCD Bias Control
The LCD COM and SEG driver enable a range of selections to be provided to suit the requirement
of the LCD panel which are being used. The bias resistor choice is implemented using the ISEL1
and ISEL0 bits in the SLCDC0 register.
SLCDC0 Register
Bit 7
Name FRAME
R/W R/W
POR 0
Bit 7 FRAME: Fram 0 or Frame 1 output selection
0: Frame 0
1: Frame 1
Bit 6~5 ISEL1~ISEL0: SCOM and SSEG operating current selection (V
00: 8.3μA
01: 16.7μA
10: 50μA
11: 100μA
Bit 4 LCDEN: SCOM and SSEG module on/off control
0: Disable
1: Enable
The SCOMn and SSEGm lines can be enabled using COMnEN and SEGmEN if
LCDEN=1. When LCDEN=0, then the SCOMn and SSEGm outputs will be fixed at a
V
SS
COM3EN: SCOM3 or other function selection
Bit 3
0: Other function
1: SCOM3
Bit 2 COM2EN: SCOM2 or other function selection
0: Other function
1: SCOM2
Bit 1 COM1EN: SCOM1 or other function selection
0: Other function
1: SCOM1
COM0EN: SCOM0 or other function selection
Bit 0
0: Other function
1: SCOM0
Rev. 1.20
BS82B12A-3/BS82C16A-3/BS82D20A-3
Touch Key 8-Bit Flash MCU with LED/LCD Driver
, or have a V
SS bias
have a Vbias value of (1/3)V
DD
, V or V . The SEG0~SEGm waveform is controlled in a similar
DD SS bias
6 5
ISEL1 ISEL0 LCDEN
R/W R/W
0 0
level.
144
, or have a V value of (1/3)V
DD bias
value of (2/3)V .
DD
, or have a V value of (2/3)V
SS bias
.
DD
, V or V
DD SS bias
4 3 2
COM�EN COM2EN COM1EN COM0EN
R/W R/W R/W
0 0 0
DD
. The
DD
. The
DD
.
1 0
R/W R/W
0 0
=5V)
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