CM68HC05C4ACFB Motorola / Freescale Semiconductor, CM68HC05C4ACFB Datasheet - Page 49

• Manufacturer Part Number: CM68HC05C4ACFB
• Description: Microcontroller
• Manufacturer: Motorola / Freescale Semiconductor

General Release Specification — MC68HC05C4A
7.1 Contents
7.2 Introduction
7.3 Port A
MC68HC05C4A
MOTOROLA
NOTE:
—
Rev. 4.0
7.2
7.3
7.4
7.5
7.6
7.7
The MC68HC05C4A has three 8-bit input/output (I/O) ports.These 24
port pins are programmable as either inputs or outputs under software
control of the data direction registers. Port D does not have a data
direction register, and its seven pins are input only with the exception of
certain SCI/SPI functions.
To avoid a glitch on the output pins, write data to the I/O port data
register before writing a 1 to the corresponding data direction register.
Port A is an 8-bit bidirectional port which does not share any of its pins
with other subsystems. The port A data register is at $0000 and the data
direction register (DDR) is at $0004. Reset does not affect the data
registers, but clears the data direction registers, thereby returning the
ports to inputs. Writing a 1 to a DDR bit sets the corresponding port bit
to output mode.
Introduction ...............................................................................49
Port A........................................................................................49
Port B........................................................................................50
Port C........................................................................................50
Port D........................................................................................51
Input/Output Programming .......................................................51
Section 7. Input/Output (I/O) Ports
Input/Output (I/O) Ports
General Release Specification
49