em78p468l ELAN Microelectronics Corp, em78p468l Datasheet - Page 16

• Manufacturer Part Number: em78p468l
• Description: 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

EM78P468N/EM78P468L
8-Bit Microcontroller
10 •
6.1.9
6.1.10 R9/LCDCR (LCD Control Register)
Bits 7~0: 8-bit I/O registers of Port 8
Bit 7 (BS): LCD bias select bit,
Bit 6 ~ 5 (DS1 ~ DS0): LCD duty select
Bit 4 (LCDEN): LCD enable bit
Bit 3: Not used
Bit 2 (LCDTYPE): LCD drive waveform type select bit
Bits 1 ~ 0 (LCDF1 ~ LCDF0): LCD frame frequency control bits
Note: Fs: sub-oscillator frequency
LCDF1
Bit 7
Bit 7
R87
BS
0
0
1
1
R8/Port 8 (Port 8 I/O Data Register)
(Address: 08h)
(Address: 09h)
DS1
User can use IOC80 register to define each bit either as input or output.
LCDEN = “1”: LCD circuit enabled.
BS = “0”: 1/2 bias
BS = “1”: 1/3 bias
LCDEN = “0”: LCD circuit disabled. All common/segment outputs are set to
LCDTYPE = “0” : A type waveform
LCDTYPE = “1” : B type waveform
0
0
1
LCDF0
Bit 6
DS1
Bit 6
R86
0
1
0
1
DS0
ground (GND) level.
0
1
×
Bit 5
DS0
Bit 5
R85
Fs/(256×2)=64.0
Fs/(280×2)=58.5
Fs/(304×2)=53.9
Fs/(232×2)=70.6
1/2 Duty
LCDEN
LCD Frame Frequency (e.g. Fs=32.768kHz)
Bit 4
Bit 4
R84
LCD Duty
(This specification is subject to change without further notice)
1/2 duty
1/3 duty
1/4 duty
Bit 3
--
Bit 3
R83
Product Specification (V1.5) 02.15.2007
Fs/(172×3)=63.5
Fs/(188×3)=58.0
Fs/(204×3)=53.5
Fs/(156×3)=70.0
1/3 Duty
LCDTYPE
Bit 2
Bit 2
R82
LCDF1
Bit 1
Bit 1
R81
Fs/(128×4)=64.0
Fs/(140×4)=58.5
Fs/(152×4)=53.9
Fs/(116×4)=70.6
1/4 Duty
LCDF0
Bit 0
Bit 0
R80