71M6534H Demo Board User’s Manual
Page: 56 of 86
© 2005-2007 TERIDIAN Semiconductor Corporation
V2-0
2.4.5 LCD
The 71M6534 has an on-chip LCD controller capable of controlling static or multiplexed LCDs. Figure 2-11
shows the basic connection for LCDs. Note that the LCD module itself has no power connection.
segments
71M653X
LCD
commons
segments
71M653X
LCD
commons
Figure 2-11: LCD Connections
2.4.6 OPTICAL INTERFACE
The 71M6534 IC is equipped with two pins supporting the optical interface: OPT_TX and OPT_RX. The
OPT_TX pin can be used to drive a visual or IR light LED with up to 20mA, a series resistor (R
2
in Figure 2-12)
helps limiting the current). The OPT_RX pin can be connected to the collector of a photo-transistor, as shown in
Figure 2-12.
R
2
R
1
Figure 2-12: Optical Interface Block Diagram
71M653X
V3P3SYS
Phototransistor
LED
100k
Ω
100pF
R
2
R
1
71M653X
V3P3SYS
Phototransistor
LED
100k
Ω
100pF
R
2
R
1
71M653X
100k
Ω
100pF
V3P3SYS
Phototransistor
LED
