em78p468n ELAN Microelectronics Corp, em78p468n Datasheet - Page 41

• Manufacturer Part Number: em78p468n
• Description: 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.6) 12.31.2007
(This specification is subject to change without further notice)
Table 3 Interrupt Vector
6.9 LCD Driver
This LSI can drive an LCD of up to 32 segments and 4 commons that can drive a total
of 4×32 dots. The LCD block is made up of an LCD driver, display RAM, segment
output pins, common output pins, and LCD operating power supply pins. This circuit
works on normal mode, green mode and idle mode. The LCD duty; bias; the number of
segment; the number of common and frame frequency are determined by the LCD
controller register.
The basic structure contains a timing control that uses a subsystem clock to generate
the proper timing for different duty and display accesses. The R9 register is a
command register for the LCD driver which includes LCD enable/disable, bias (1/2 and
1/3), duty (1/2, 1/3, 1/4), and LCD frame frequency control. The register RA is an LCD
contrast and LCD RAM address control register. The register RB is an LCD RAM data
buffer. LCD booster circuit can change the operation frequency to improve VLCD2 and
VLCD3 drive capability. The control register is described as follows.
6.9.1 R9/LCDCR (LCD Control Register)
Bit 7 (BS): LCD bias select bit, 0/1=> (1/2 bias) / (1/3 bias)
Bits 6 ~ 5 (DS1 ~ DS0): LCD duty select
Bit 4 (LCDEN): LCD enable bit
Bit 7
BS
Interrupt Vector
“0”: disable the LCD circuit
“1”: enable the LCD circuit
DS1
0
0
1
000CH
0003H
0006H
0009H
000FH
0012H
0015H
0018H
Bit 6
DS1
DS0
0
1
×
Bit 5
DS0
TCC overflow interrupt.
External interrupt P5.4/INT0 pin
External interrupt P5.5/INT1 pin
Counter 1 underflow interrupt
Counter 2 underflow interrupt
High-pulse width timer underflow interrupt
Low-pulse width timer underflow interrupt
Port 6, Port 8 input status change wake up
LCDEN
Bit 4
LCD Duty
1/2 duty
1/3 duty
1/4 duty
Interrupt Status
Bit 3
−
LCDTYPE
Bit 2
8-Bit Microcontroller
LCDF1
Bit 1
EM78P468N/L
LCDF0
Bit 0
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