16-Bit Mixed-Signal Microcontroller

with LCD Interface

______________________________________________________________________________________

17

Pin Description (continued)

PIN

NAME

FUNCTION

43

LCD Bias, Voltage 2. LCD drive voltage used with 1/3 LCD bias. An internal resistor-divider

sets the voltage. External resistors and capacitors can be used to change LCD voltage or

drive capability at this pin.

42

LCD Adjustment Voltage. Connect to an external resistor to provide external control of the LCD

contrast. Leave disconnected for internal contrast adjustment.

GENERAL-PURPOSE I/O, SPECIAL FUNCTION, AND LCD INTERFACE PINS

Digital I/O, Type D Port 0; LCD Segment-Driver Output; External Edge-Selectable Interrupt.

This port functions as either bidirectional I/O or alternate LCD segment-drive outputs. The reset

condition of the port is with all bits at logic 1. In this state, a weak pullup holds the port high.

This condition serves as an input mode. Each port pin can individually be configured to act as

an external interrupt. Setting the PCF0 bit switches all pins on this port to LCD segment-drive

outputs.

It is possible to mix the LCD and interrupt functions on the same port. To do this, the interrupt

enable must be established prior to setting the PCF0 bit. Care must be taken not to enable the

external interrupt while the LCD is in normal operational mode, as this could result in

potentially harmful contention between the LCD controller output and the external source

connected to the interrupt input.

PIN

PORT

SPECIAL/ALTERNATE FUNCTION

6

P0.0

SEG0

INT0

5

P0.1

SEG1

INT1

4

P0.2

SEG2

INT2

3

P0.3

SEG3

INT3

2

P0.4

SEG4

INT4

1

P0.5

SEG5

INT5

94

P0.6

SEG6

INT6

6–1, 94, 93

P0.0–P0.7;

SEG0–SEG7;

INT0–INT7

93

P0.7

SEG7

INT7

Digital I/O, Type C Port 1; LCD Segment-Driver Output. This port functions as either

bidirectional I/O or alternate LCD segment-drive outputs. The reset condition of the port is with

all bits at logic 1. In this state, a weak pullup holds the port high. This condition serves as an

input mode. The port pins also contain a Schmitt voltage input. Setting the PCF1 bit switches

all pins on this port to LCD segment-drive outputs.

PIN

PORT

SPECIAL/ALTERNATE FUNCTION

91

P1.0

SEG8

90

P1.1

SEG9

89

P1.2

SEG10

88

P1.3

SEG11

87

P1.4

SEG12

86

P1.5

SEG13

85

P1.6

SEG14

91–84

P1.0–P1.7;

SEG8–SEG15

84

P1.7

SEG15