HT46R064D/065D/066D
Enhanced A/D Type 8-Bit OTP MCU with LED Driver
Only the Program Counter is pushed onto the stack. If the contents of the register or status register are
altered by the interrupt service program, which may corrupt the desired control sequence, then the
contents should be saved in advance.
SCOM Function for LCD
The devices have the capability of driving external LCD panels. The common pins for LCD driving,
SCOM0~ SCOM3, are pin shared with certain pin on the PB6~ PB7, PC6~PC7 port. The LCD signals
(COM and SEG) are generated using the application program.
LCD Operation
An external LCD panel can be driven using this device by configuring the PB0~PB3 pins as common
pins and using other output ports lines as segment pins. The LCD driver function is controlled using
the SCOMC register which in addition to controlling the overall on/off function also controls the bias
voltage setup function. This enables the LCD COM driver to generate the necessary VDD/2 voltage
levels for LCD 1/2 bias operation.
The SCOMEN bit in the SCOMC register is the overall master control for the LCD Driver, however
this bit is used in conjunction with the COMnEN bits to select which Port B and Port C pins are used
for LCD driving. Note that the Port Control register does not need to first setup the pins as outputs to
enable the LCD driver operation.
SCOMEN
COMnEN
Pin Function
I/O
O/P Level
0 or 1
0
1
1
X
0
1
I/O
0 or 1
SCOMN
VDD/2
Output Control
Rev. 1.00
70
January 12, 2011
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
