sh66l08a SinoWealth Micro-Electronics Corp. Ltd, sh66l08a Datasheet - Page 13

• Manufacturer Part Number: sh66l08a
• Description: 1k 4-bit Micro-controller With Lcd Driver
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

9. LCD Driver
The LCD driver contains a controller, a voltage generator, 4 common driver pads and 34 segment driver pads. There are two
different driving modes: 1/4 duty and 1/3 bias, 1/3 duty and 1/2 bias (COM4 same as COM1). The driving mode is controlled by
code option. The controller consists of display data RAM and a duty generator. The LCD data RAM is a dual port RAM that transfers
data to segment pads automatically without program control.
PORTC, PORTD can be used as LCD SEG27 - 34. It is selected by Bit2 and Bit1 of system register $15. But if the PORTD.2 -
3 is selected as input only controlled by code option, these ports can’t be used as LCD SEG33 - 34. When used as I/O ports, the
data in LCD RAM does not affect the I/O input and output data. Also, when used as LCD output, the I/O RAM data won't affect
LCD output. LCD RAM can be used as data memory if needed.
When the “STOP” instruction is executed, the LCD will be turned off, but the data of LCD RAM keeps the value.
When LCD off, both common and segment output low.
System Register $13:
*: Please refer to the “Program Notes” described as below for details.
Heavy Load Mode (HLM): This mode is designed for the 32kHz crystal oscillator, so that the oscillation can be maintained in a
noisy power environment. The power might drop suddenly when the ALARM is driving a speaker. The HLM is designed to
control this power variation. The consumption of power will increase during the use of the HLM mode, but it will not affect the RC
oscillator.
LCD Frame Frequency
The LCD Frame Frequency has two modes when the chip is used in RC application. The mode is controlled by the “Clock
source” code option.
The code option and LCD Frame Frequency are shown as below:
Address
Address
32.768kHz Crystal
131kHz RC with normal LCD frame frequency
131kHz RC with 1/2 LCD frame frequency
$13
$15
PPULL
Bit 3
Bit 3
X
X
X
X
X
X
X
X
X
X
-
Code Option
LCDOFF
O/S2
Bit 2
Bit 2
X
X
X
X
X
X
0
1
0
1
O/S1
Bit 1
HLM
Bit 1
X
X
X
X
X
X
0
1
0
1
Bit 0
PAM
Bit 0
X
X
X
X
0
1
-
-
-
-
-
1/3 duty, 1/2 bias
R/W
R/W
R/W
R/W
About 43Hz
About 43Hz
About 21Hz
13
Bit0: PORTA.1, PORTA.2 as Alarm O/P control register
Bit1: Heavy load Mode control register
Bit2: LCD power control register
PORTA.1, PORTA.2 as I/O port
PORTA.1, PORTA.2 as ALARM output
No heavy load
Heavy Load mode
LCD display on, pump on
LCD display off, pump off *
Bit1: PORTC as LCD segment output control register
Bit2: PORTD as LCD segment output control register
Bit3: Port pull-up control register
PORTC as I/O port
PORTC as LCD SEG27 - 30
PORTD as I/O ports
PORTD as LCD SEG31 - 34
LCD frame frequency
Remarks
Remarks
1/4 duty, 1/3 bias
About 32Hz
About 32Hz
About 16Hz
SH66L08A