XC68HC705JB3 Motorola, XC68HC705JB3 Datasheet - Page 47

• Manufacturer Part Number: XC68HC705JB3
• Description: MICROCONTROLLER
• Manufacturer: Motorola

7.1
MC68HC05JB3
REV 1
Port Pins
PB1, PB2
PA0-PA3
PA4-PA7
PB4-PB7
PC1-PC3
Notes:
In normal operating mode there are 19 usable bidirectional I/O lines arranged as
one 8-bit I/O port (Port-A), one 7-bit I/O port (Port-B), and one 4-bit I/O port
(Port C). The individual bits in these ports are programmable as either inputs or
outputs under software control by the data direction registers (DDRs).
The eight port pins, PB4-PB7 and PC0-PC3, are only available on the 28-pin
version of the device.
Table 7-1 shows a summary of Port-A, Port-B, and Port-C functions.
PC0
PORT-A
Port-A is an 8-bit bi-directional port. The Port-A data register is at $0000 and the
data direction register (DDRA) is at $0004. Reset does not affect the data regis-
ters, but clears the data direction registers, thereby returning the port pins to
inputs. Writing a ‘1’ to a DDR bit sets the corresponding port bit to output mode.
All Port-A pins have programmable pull-down resistors. PA4 to PA7 each has 8mA
current sink capability.
The table below summarizes the pin configurations for Port-A.
PB0
1.
2.
A pull-up/pull-down resistor is enabled by setting the corresponding register bit to “0” and the
port pull-up/down mask option is selected.
Selected by mask option.
Internal Resistor
Configuration
Table 7-1. Summary of Port Pin Functions
Pull-down
Pull-down
Pull-up
1
1
1
INPUT/OUTPUT PORTS
INPUT/OUTPUT PORTS
November 5, 1998
SECTION 7
Drive/Sink
1.6mA sink
1.6mA sink
25mA sink,
1.6mA sink
open-drain
8mA sink
Current
shared with OCMP
External Interrupt
shared with TCAP
GENERAL RELEASE SPECIFICATION
Additional Features
Slow Transition Output
2
Pins available only
Optical Interface
in 28-pin device
MOTOROLA
7-1