Samsung 8-Bit CMOS Microcontroller, S3C9228/P9228 user manual Lcd Controller/Driver

S3C9228/P9228 LCD CONTROLLER/DRIVER

13 LCD CONTROLLER/DRIVER

OVERVIEW

The S3C9228/P9228 microcontroller can directly drive an up-to-128-dot (16segments x 8 commons) LCD panel. Its LCD block has the following components:

—LCD controller/driver

—Display RAM for storing display data

—16 segment output pins (SEG0–SEG15)

—8 common output pins (COM0–COM7)

—Internal resistor circuit for LCD bias

To use the LCD controller, bit 2 in the watch mode register WMOD must be set to 1 because LCDCK is supplied by the watch timer.

The LCD mode control register, LMOD, is used to turn the LCD display on or off, to select LCD clock frequency, to turn the COM signal output on or off, to select bias and duty, and to switch the port 3 high impedance or normal I/O port. Data written to the LCD display RAM can be transferred to the segment signal pins automatically without program control.

The LCD port control register, LPOT, is used to determine the LCD signal pins used for display output.

When a sub clock is selected as the LCD clock source, the LCD display is enabled even during main clock stop and idle modes.

Data BUS

8

LCD

Controller/

Driver

4

4

COM0-COM3

COM4/SEG19- COM7/SEG16

16

SEG0/P2.1- SEG15/P5.3

Figure 13-1. LCD Function Diagram

13-1