ATXMEGA128B1_14 Datasheet, PDF (48/142 Pages) ATMEL Corporation – 8/16-bit Atmel XMEGA B1 Microcontroller

28. LCD - Liquid Crystal Display Controller
28.1
Features
 Display capacity up to 40 segment and up to 4 common terminals
 Supports up to 16 GPIO's
 Shadow display memory gives full freedom in segment update
 ASCII character mapping
 Swap capability option on segment and/or common terminal buses
 Supports from static up to 1/4 duty
 Supports static and 1/3 bias
 LCD driver active in power save mode for low power operation
 Software selectable low power waveform
 Flexible selection of frame frequency
 Programmable blink mode and frequency on two segment terminals
 Uses Only 32 kHz RTC clock source
 On-chip LCD power supply
 Software contrast adjustment control
 Equal source and sink capability to Increase glass life time
 Extended interrupt mode for display update or wake-up from sleep mode
28.2
Overview
The LCD controller is intended for monochrome passive liquid crystal display (LCD) with up to 4 Common terminals and
up to 40 Segments terminals. If the application does not need all the LCD segments available on the XMEGA, up to 16 of
the unused LCD pins can be used as general purpose I/O pins.
The LCD controller can be clocked by an internal or an external asynchronous 32kHz clock source. This 32kHz oscillator
source selection is the same as for the real time counter (RTC).
Dedicated Low Power Waveform, Contrast Control, Extended Interrupt Mode, Selectable Frame Frequency and Blink
functionality are supported to offload the CPU, reduce interrupts and reduce power consumption.
To reduce hardware design complexity, the LCD includes integrated LCD buffers, an integrated power supply voltage
and an innovative SWAP mode. Using SWAP mode, the hardware designers have more flexibility during board layout as
they can rearrange the pin sequence on Segment and/or Common Terminal Buses.
Figure 28-1. LCD overview
Character
Mapping
Timing
Control & Swap
Display
Memory
Shadow
Display
Memory
Analog
Switch
Array
SEG[39:0]
COM[3:0]
LCD Power
Supply
CAPH
CAPL
VLCD
BIAS1
BIAS2
XMEGA B1 [DATASHEET] 48
Atmel-8330F-AVR-ATxmega64B1-128B1_datasheet–AVR–02/2014