mc68hc05ct4fn Freescale Semiconductor, Inc, mc68hc05ct4fn Datasheet - Page 55

• Manufacturer Part Number: mc68hc05ct4fn
• Description: Mc68hc05 Family Of Microcontrollers Mcus
• Manufacturer: Freescale Semiconductor, Inc

General Release Specification — MC68HC05CT4
7.1 Contents
7.2 Introduction
7.3 Port A
MC68HC05CT4
NOTE:
—
Rev. 2.0
7.2
7.3
7.4
7.5
7.6
7.7
In user mode 31 lines are arranged as one 7-bit and three 8-bit ports.
Most of these port pins are programmable as either inputs or outputs
under software control of the data direction registers, though some are
input only.
To avoid a glitch on the output pins, write data to the I/O port data
register before writing a logic 1 to the corresponding data direction
register.
Port A is an 8-bit bidirectional port that 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 logic 1 to a DDR bit sets the corresponding port
bit to output mode.
Freescale Semiconductor, Inc.
For More Information On This Product,
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Port A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Port B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Port C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Port D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Input/Output Port Pin Programming . . . . . . . . . . . . . . . . . . . . .57
Section 7. Parallel Input/Output (I/O)
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Parallel Input/Output (I/O)
General Release Specification