BS85B12-3 HOLTEK [Holtek Semiconductor Inc], BS85B12-3 Datasheet - Page 148

• Manufacturer Part Number: BS85B12-3
• Description: Touch Key Flash Type 8-Bit MCU with LCD/LED Driver
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

LCD Driver - SCOM and SSEG Function
Rev. 1.00
LCD Operation
The devices can drive LCD panels by simulating LCD signals on their I/O pins using the application
program. Both Command and Segment signals can be emulated in this way.
The LCD driving Common pins, SCOM0~SCOM3, and Segment pins, SSEG0~SSEGn, are pin
shared with other I/O pins. These LCD driving pins are configured using a series of LCD control
registers which in addition to controlling the overall on/off function also controls the bias voltage setup
function. This enables the LCD COM and SEG driver to generate the necessary VSS, (1/3)VDD,
(2/3)VDD voltage and VDD levels for full LCD 1/3 bias operation.
The SLCDEN bit in the LCD control register is the overall master control for the LCD driver, and this
bit is used in conjunction with the COMnEN and SEGnEN bits to select which I/O Port 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.
Touch Key Flash MCU with LCD/LED Driver
LCD Driver Structure
142
BS85B12-3/BS85C20-3
February 1, 2011