Maxim Integrated MAXQ Family Users Guide: MAXQ2000 Supplement - Manual (Page 66)

LCD CONTROLLER (SPECIFIC TO MAXQ2000)
The MAXQ2000 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.
LCD Controller Features
• 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
• 68-pin package: Up to 36 segment (SEG0 to SEG35) outputs and four common (COM0 to COM3) outputs
• 56-pin package: Up to 28 segment (SEG0 to SEG27) outputs and four common (COM0 to COM3) outputs
• Unused segment outputs can be used as general-purpose port pins
• 17 bytes (136 bits) of display memory
• Unused display memory can be used for general-purpose storage
• Flexible LCD clock source, selectable from 32kHz or HFClk / 128
• 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
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
SEG35
COM0
COM1
COM2
COM3
V LCD
V LCD1
V LCD2
V ADJ
VOLTAGE CONTROL
Figure 8. LCD Controller Block Diagram
MAXQ Family User’s Guide:
MAXQ2000 Supplement
Maxim Integrated 66