Maxim Integrated MAXQ Family Users Guide: MAXQ2000 Supplement - Manual (Page 80)

Display Waveform Generation
Once the operational modes and display memory registers on the LCD controller have been properly initialized, the controller gener-
ates the segment and common drive waveforms needed to display the enabled segments on the attached LCD display.
In static mode, each segment pin is connected to a single LCD segment. There is only one common, or backplane, signal, which is
driven by COM0. All ON segments are driven for the entire frame period.
In x2-multiplexed mode, also known as 1/2 duty cycle mode, each segment pin can drive up to two LCD segments. There are two com-
mon backplane signals, driven by COM0 and COM1. Each ON segment is only driven for half of the frame period.
In x3-multiplexed mode, also known as 1/3 duty cycle mode, each segment pin can drive up to three LCD segments. There are three
common backplane signals, driven by COM0, COM1 and COM2. Each ON segment is only driven for 1/3 of the frame period.
In x4-multiplexed mode, also known as 1/4 duty cycle mode, each segment pin can drive up to four LCD segments. There are four
common backplane signals, driven by COM0, COM1, COM2 and COM3. Each ON segment is only driven for 1/4 of the frame period.
In each of the following examples, the LCD controller is driving a “2” to the display. This is a conventional seven-segment display, and
the “2” consists of ON segments a, b, d, e, g, and DP as shown in Figure 11. The voltage waveforms shown assume that V
ADJ equals
ground (R ADJ is set to 0Ω). The portions of the memory maps used apply to either package type.
LCD Controller Static Drive Example
In this example, SEG0 through SEG7 are used to drive the LCD segments. The segments and common signals are connected as shown
in Figure 12.
MAXQ Family User’s Guide:
MAXQ2000 Supplement
a
b
c
d
f
g
e
DP
a
b
c
d
f
g
e
DP
Figure 11. Sample 7-Segment LCD Display
COM0
SEG1
SEG2
SEG3
SEG5
SEG0
SEG7
SEG6
SEG4
Figure 12. Static Drive Example Display Connection
Maxim Integrated 80