43.
SLCD - Segment Liquid Crystal Display Controller
43.1. Overview
An LCD display is made of several segments (pixels or complete symbols) which can be visible or
invisible. A segment has two electrodes with liquid crystal between them. These electrodes are the
common terminal (COM pin) and the segment terminal (SEG pin). When a voltage above a threshold
voltage is applied across the liquid crystal, the segment becomes visible.
The LCD controller is intended for monochrome passive liquid crystal display (LCD) with up to 8 common
terminals and up to 44 segment terminals. A charge pump provides LCD display supply which can be
higher than supply voltage of the device. Each LCD pin, segment or common terminals, can be
configured as general purpose I/O pins if not driven by LCD controller.
Several features such as character mapping, automated characters string display, autonomous animation
are implemented to reduce CPU load and power consumption.
Figure 43-1. LCD Panel - Segment/Common Terminals Connections
segment 0
segment 1
segment 2
segment 42
segment 41
segment 40
COM0
COM1
SEG0
SEG1
SEG2
...
...
Note:
In order to avoid degradation due to electrophoresis in the liquid crystal, the waveform of the
voltage across a segment must not have a DC component.
43.2. Features
•
Display capacity up to 44 segments lines and up to 8 common lines (up to 320 segments)
•
Selection of maximum 48 segment/common lines from 52 LCD pins
•
Support from static up to 1/8 duty
•
Support static, 1/2, 1/3 and 1/4 bias
•
Shadow display memory for full freedom in segment update
•
LCD pins as segment terminal, common terminal or general purpose I/O
•
Blink mode and frequency configuration (up to 16 segments)
•
Regular and low power waveform
•
Software contrast adjustment control
•
On-chip LCD power supply
•
Character mapping
•
Automated characters string scrolling
•
Automated characters string display
•
Automated segments display
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
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