SAK-C505L Infineon Technologies AG, SAK-C505L Datasheet - Page 38

• Manufacturer Part Number: SAK-C505L
• Description: 8-bit CMOS Microcontroller
• Manufacturer: Infineon Technologies AG

LCD Controller Unit
The Liquid Crystal Display (LCD) controller unit in the C505L is designed for the control of an LCD
display module of 128 display segments (4 rows and 32 columns) using the 1/4 duty-cycle driving
method. The C505L can be programmed to generate reference voltages for adjusting the contrast
of the display.
An example of a typical LCD module is shown in Figure 16. The table describes the different
combinations of the row and column signals required to activate a particular segment. The signals
R0-R3 and C0-C31 are the row and column signals, respectively, connected to the display module.
Figure 16
Organization of a Typical LCD Display Module
The memory required by the LCD controller includes a control register, LCON, the D/A Converter
register DAC0 and 16 individual digit registers (DIGx, x = 0 to F). These registers are implemented
in the on-chip external data memory area. Accesses to these registers are similar to on-chip XRAM
accesses (MOVX instructions) and therefore must be preceded by an enable operation on the on-
chip XRAM.
Note: The actual segment organization within the display unit could be different from the example
The LCD outputs of the C505L must work at a frequency which is not more than 360 Hz in order to
activate a display segment. To achieve this 360-Hz frequency limit, the LCD controller uses a
scheme as shown in Figure 17.
Data Sheet
considered here. In such cases, the segment names/positions may vary. The user should
consult the manufacturer of the LCD display unit used regarding its segment organization.
R3
R2
R1
R0
C1
F
E
A
G
D
H
B
C
C0
36
Rows
R3
R2
R0
R1
C1
G
E
D
F
Columns
MCD03858
C0
A
B
C
H
C505L
06.99