MC68HC05P18 Datasheet, PDF (64/144 Pages) Freescale Semiconductor, Inc – Advance Information

Freescale Semiconductor, Inc.
Input/Output (I/O) Ports
7.3 Port A
Port A is an 8-bit bidirectional port which can share its pins with the IRQ
interrupt system as shown in Figure 7-1. Each port A pin is controlled by
the corresponding bits in a data direction register and a data register.
The port A data register is located at address $0000. The port A data
direction register (DDRA) is located at address $0004. Reset clears the
DDRA, thereby initializing port A as an input port. The port A data
register is unaffected by reset.
READ $0004
WRITE $0004
WRITE $0000
READ $0000
MOR 2
(PULLUP INHIBIT)
DATA DIRECTION
REGISTER BIT
DATA
REGISTER BIT
V_DD
OUTPUT
I/O
PIN
INTERNAL
HC05
DATA BUS
RESET
(RST)
Figure 7-1. Port A I/O Circuitry
100 µA
PULLUP
TO IRQ INTERRUPT
SYSTEM
Advance Information
64
MC68HC(8)05P18 — Rev. 2.0
Input/Output (I/O) Ports
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