MC9S08LC60 Introduction
Interfacing an LCD to the MC9S08LC60, Rev. 0
Freescale Semiconductor
3
The multiplexing configuration relates to the LCD duty cycle. The duty cycle indicates the amount of time
the LCD panel segment is energized during each LCD module frame cycle. The available duty cycle
options for the MC9S08LC60 LCD module are 1/2, 1/3, and 1/4. The denominator of the duty cycle
indicates the number of backplanes being used to drive a LCD panel.
This application note does not provide an introduction to LCD theory, types of LCD, LCD waveforms, or
principles of operation. AN3219,
XGATE Library: TN/STN LCD Driver,
provides a detailed description
of driving TN and STN LCDs using general-purpose input/output (GPIO) pins. Even though the
MC9S08LC60 has a built-in LCD driver module, the discussions presented in AN3219 on multiplex
waveforms and LCD theory are relevant.
1.2
Number of Segments and Using Segments in LCD
Depending on package and LCD configuration, the MC9S08LC60 can support up to 160 segments. The
number of segments is equal to the number of backplanes times the number of frontplanes. With multiplex
LCD drivers like the MC9S08LC60, each frontplane pin can be connected to as many segments as there
are backplanes. With up to 160 segments, the MC9S08LC60 can be used in displays that are numeric,
alpha-numeric, symbolic, or a combination of these. Numeric displays require seven segments for each
digit; alpha-numeric displays require either 14 or 16 segments per character.
lists the available
configurations and the potential number of digits when using a 7-, 14-, or 16-segment configuration.
Table 1. 9S08LC60 Segment Configuration Based on Package
Package
Number of
Backplanes
Number of
Frontplanes
Total Number of
Segments
Potential Number of Characters (Remainder)
7 segment
14 segment
16 segment
64 pin
4
32
128
18 (2)
9 (2)
8 (0)
3
33
99
14 (1)
7 (1)
6 (3)
80 pin
4
40
160
22 (6)
11 (6)
10 (0)
3
41
123
17 (4)
8 (11)
7 (11)
