sh66k51a SinoWealth Micro-Electronics Corp. Ltd, sh66k51a Datasheet - Page 22

• Manufacturer Part Number: sh66k51a
• Description: 2k 4-bit Micro-controller With Lcd Driver
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

10. LCD Driver
The LCD driver contains a controller, a voltage regulator generator, 6 common driver pins and 26 segment driver pins.
There are four different driving programmable modes: 1/3 duty and 1/3 bias, 1/4 duty and 1/3 bias, 1/5 duty and 1/3 bias
and 1/6 duty and 1/3 bias. The driving mode is controlled by the system register $15 and the power on initialization status is
1/4 duty, 1/3 bias.
When 1/5 duty and 1/3 bias mode are used, COM6 is used as SEG27.
When 1/4 duty and 1/3 bias mode are used, COM5 - 6 are used as SEG28 - 27.
When 1/3 duty and 1/3 bias mode are used, COM4 - 6 are used as SEG29 - 27.
The controller consists of display data RAM and a duty generator.
The LCD SEG1 - 4 can also be used as I/O port (PORTC), which is selected by bit2 of the system register $15 and the LCD
SEG5 - 8 can also be used as I/O port (PORTD), which is selected by bit3 of the system register $15. 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 value.
When LCD off, both common and segment output low.
10.1. LCD Control Register
LCD Segment:
LCD Duty:
DUTY1, DUTY0: LCD duty control
LCD Clock:
LCD clock is divided from OSC, so LCD frame frequency will change in proportion to the variation of OSC frequency in spite
of OSC type.
Address
Address
Address
FRAME Frequency (When f
$07
$15
$15
$15
O/S1
O/S1
O/S1
Bit 3
Bit 3
Bit 3
X
X
X
X
X
X
0
1
-
IN 1/6 DUTY MODE
IN 1/5 DUTY MODE
IN 1/4 DUTY MODE
IN 1/3 DUTY MODE
LCDON
O/S0
O/S0
O/S0
Bit 2
Bit 2
Bit 2
0
1
X
X
X
X
X
X
OSC
DUTY1
DUTY1
DUTY1
= 32.768kHz/131kHz RC)
Bit 1
Bit 1
Bit 1
X
X
X
X
0
0
1
1
-
DUTY0
DUTY0
DUTY0
Bit 0
Bit 0
Bit 0
X
X
X
X
0
1
0
1
-
R/W
R/W
R/W
R/W
R/W
R/W
R/W
22
Bit2: Set LCD display on
Bit0, 1: Select LCD duty (1/3, 1/4, 1/5 or 1/6)
Bit2: Set PORTC as LCD SEG 1 - 4
Bit3: Set PORTD as LCD SEG 5 - 8
Bit2: Select PORTC or LCD segment
Bit3: Select PORTD or LCD segment
PORTC as I/O ports
PORTC as LCD SEG 1 - 4
PORTD as I/O ports
PORTD as LCD SEG 5 - 8
Bit0, 1: LCD duty control
LCD driver = 1/4 duty, 1/3 bias
LCD driver = 1/3 duty, 1/3 bias
LCD driver = 1/5 duty, 1/3 bias
LCD driver = 1/6 duty, 1/3 bias
42.7Hz
34.1Hz
42.7Hz
32Hz
Remarks
Remarks
Remarks
SH66K51A