ay0438 Microchip Technology Inc., ay0438 Datasheet - Page 4

• Manufacturer Part Number: ay0438
• Description: 32-segment Cmos Lcd Driver
• Manufacturer: Microchip Technology Inc.

AY0438
1.4
In order to avoid any race conditions, the Data In and
Load signals should not be changed during a falling
edge of the Clock. Figure 4 and Figure 7 show a typical
timing diagram for a 32 segment and 64 segment LCD
module.
FIGURE 8: INTERFACING TO A LCD MODULE AND PIC16CXX DEVICE
EXAMPLE 1:
;*************************************************************************
;This program shows an interface between a PIC16CXX device
;and the AY0438 LCD controller to control a 7 Segment
;4 digit LCD module.
;The PIC16CXX interface to the AY0438 Hardware:
;
;
;
;
;
;The LCD module is connected to the AY0438 as follows:
;
;
;
;
;
DS70010I-page 4
General
PORTB bit 0 --> CLK
PORTB bit 1 --> DATA IN
PORTB bit 2 --> LOAD
Most Significant digit
3rd Significant digit
2nd Significant digit
Least Significant digit --> seg25 to seg 31
PIC16CXX
RB7
EXAMPLE CODE
RB0
RB1
RB2
Clock
Data In
Load
LCD
AY0438
--> seg1 to seg7
--> seg9 to seg15
--> seg17 to seg 23
SEG19-23
SEG25-31
Backplane
SEG9-15
SEG1
SEG7
SEG6
SEG5
SEG4
SEG3
SEG2
1.5
Figure 8 shows a typical layout of an AY0438 con-
nected to a LCD module and interfaced to a PIC16CXX
family device. Example 1 lists code used to program
the PIC16CXX device. This code was complied using
MPASM.
SEG G
SEG D
SEG C
SEG A
SEG F
SEG E
SEG B
Interfacing to a LCD Module and
PIC16CXX Device
F G
E
A
D
B
C
7
7
1995 Microchip Technology Inc.
7
LCD
Backplane