sh6611a SinoWealth Micro-Electronics Corp. Ltd, sh6611a Datasheet - Page 9

• Manufacturer Part Number: sh6611a
• Description: 1k 4-bit Microcontroller With Lcd Driver
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

8. LCD Driver
The LCD driver contains a controller, a voltage generator, 4 common signal pins and 26 segment driver pins. There are two
different driving modes programmable: one is 1/4 duty and 1/3 bias, the other is 1/3 duty and 1/2 bias. The driving mode is
controlled by system register $15 and the power on initialization status is 1/3 duty, and 1/2 bias. 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 pins
automatically without a program control.
The LCD SEG1 - 4 can also be used as output port, it is selected by the bit 3 of the system register $13. When SEG1 - 4 are
output ports, data can be written to bit 0 of the same addresses (300H-303H). LCD RAM could 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 same
value before executing the "STOP" instruction.
(a) LCD Control Register
(b) LCD divider resistance control (code option)
Low LCD Driving Capability :
Normal LCD Driving Capability :
High LCD Driving Capability :
Higher LCD Driving Capability :
When large LCD panel is used, user can select smaller divider resistance through code option to increase the bias current
for better LCD performance. But it will cost more power, when smaller divider resistance is used.
(c) Configuration of LCD RAM area
(1) When segments 1 - 4 are used as output ports:
System Register $13
System Register $15
Address
300H
301H
302H
303H
PAM:
HLM:
LCDOFF:
O/S:
DUTY: LCD duty control
Total Internal LCD divider resistance is 1.44M.
Total Internal LCD divider resistance is 360K.
Total Internal LCD divider resistance is 165K.
Total Internal LCD divider resistance is 120K.
$13
$15
PORTA Mode control:
Bit 3
Seg1 – 4 control:
Bit 3
LCD Power control:
Heavy load mode control:
O/S
COM4
Bit 3
-
-
-
-
-
0: PORTA.1, PORTA.2 as I/O port
0: No heavy load
0: LCD signal on
0: Seg1 - 4 as LCD output
0: 1/3 duty, 1/2 bias
LCDOFF
Bit 2
Bit 2
-
COM3
Bit 2
-
-
-
-
Bit 1
HLM
Bit 1
-
1: HEAVY LOAD mode
1: LCD signal off
DUTY
Bit 0
PAM
Bit 0
COM2
Bit 1
-
-
-
-
9/25
1: Seg1 - 4 as output ports
1: 1/4 duty, 1/3 bias
R/W
R/W
R/W
R/W
DATA_BIT
DATA_BIT
DATA_BIT
DATA_BIT
1: PORTA.1, PORTA.2 as ALARM output
COM1
Bit 0
Bit0: set PA.1, PA.2 as Alarm O/P
Bit1: HEAVY LOAD Mode
Bit2: LCD off
Bit3: set LCD segment as outport
LCD duty control
Description
Description
SH6611A
Ver 0.0