LCD Controller Operation
18-4 LCD Controller
18.2 LCD Controller Operation

The LCD controller is configured with user software. The setup and operation

of LCD controller is discussed in the following sections.

18.2.1 LCD Memory

The LCD memory map is shown in Figure 182. Each memory bit corresponds

to one LCD segment, or is not used, depending on the mode. To turn on an

LCD segment, its corresponding memory bit is set.

Figure 182. LCD memory

--
32103210
Associated
Common Pins
097h
Address
---- ------
------ ------
------ ------
------ ------
------ ------
------ ------
------ ------
------ ------
------ ------
------ ------
------ ------
------ ------
------ ------
------ ------
------ ------
098h
099h
09Ah
09Bh
09Ch
09Dh
09Eh
09Fh
0A0h
0A1h
0A2h
0A3h
0A4h
29, 28
27, 26
25, 24
23, 22
21, 20
19, 18
17, 16
15, 14
13, 12
11, 10
9, 8
7, 6
5, 4
3, 2
1, 0
70
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
Associated
Segment Pins
Sn+1 Sn
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
n
------ ------
------ ------
------ ------
------ ------
------ ------
--
--
--
--
--
--
--
--
--
--
092h
093h
094h
095h
096h
31, 30
33, 32
35, 34
37, 36
39, 38
30
32
34
36
38
091h

18.2.2 Blinking the LCD

The LCD controller supports blinking. The LCDSON bit is ANDed with each

segments memory bit. When LCDSON = 1, each segment is on or off

according to its bit value. When LCDSON = 0, each LCD segment is off.

18.2.3 LCD Timing Generation

The LCD controller uses the fLCD signal from the Basic Timer1 to generate the

timing for common and segment lines. The proper frequency fLCD depends on

the LCDs requirement for framing frequency and LCD multiplex rate. See the

Basic Timer1 chapter for more information on configuring the fLCD frequency.