Maxim Integrated MAXQ Family Users Guide: MAXQ2010 Supplement - Manual (Page 93)

MAXQ Family User’s Guide:
MAXQ2010 Supplement
20-1
SECTION 20: LCD CONTROLLER (SPECIFIC TO MAXQ2010)
20.1 LCD Controller Overview
The MAXQ2010 provides an on-board LCD controller module that can generate segment and common signals for an
LCD based on display memory content. Once the LCD controller settings and display memory have been initialized,
the LCD segment and common signals are generated automatically at the selected display frequency. No additional
processor overhead is required while the LCD controller is running.
The LCD controller provides the following features and modes:
• Automatic LCD segment and common drive signal generation
• Four types of display modes supported:
Static
1/2 duty multiplexed with 1/2 bias voltages
1/3 duty multiplexed with 1/3 bias voltages
1/4 duty multiplexed with 1/3 bias voltages
• Up to 43 segment (SEG0 to SEG42) outputs and four common (COM0 to COM3) outputs
• Unused segment outputs SEG0 to SEG39 can be used as general-purpose port pins
• 21 bytes (168 bits) of display memory
• Unused display memory can be used for general-purpose storage
• Flexible LCD clock source, selectable from 32kHz or (high-frequency clock source/512)
• Adjustable frame frequency
• Internal voltage-divider resistors eliminate requirement for external components
• Internal adjustable resistor allows contrast adjustment without external components
• Capability to use external resistors to adjust drive voltages and current capacity
Figure 20-1. LCD Controller Block Diagram
FRAME
FREQUENCY
TIMING CONTROL
SEGMENT DRIVER
COMMON DRIVER
WAVEFORM GENERATION
DISPLAY MEMORY
(REGISTER FILE)
LCFG
OPM
LCRA
DPE
PCF
LRIG
BIAS
DUTY
FRM
f LCD f FRAME
SEG0
SEG39
COM0
COM1/SEG42
COM2/SEG41
COM3/SEG40
V LCD
V LCD1
V LCD2
V ADJ
VOLTAGE CONTROL