MC68HC08AZ32A Datasheet, PDF (310/456 Pages) Motorola, Inc – HCMOS Microcontroller Unit

I/O Ports
Freescale Semiconductor, Inc.
19.7.2 Data Direction Register E (DDRE)
Data direction register E determines whether each port E pin is an input
or an output. Writing a logic one to a DDRE bit enables the output buffer
for the corresponding port E pin; a logic zero disables the output buffer.
Bit 7
6
5
4
3
2
1
Bit 0
DDRE
$000C
Read:
DDRE7 DDRE6 DDRE5 DDRE4 DDRE3 DDRE2 DDRE1 DDRE0
Write:
Reset: 0
0
0
0
0
0
0
0
Figure 19-14. Data Direction Register E (DDRE)
DDRE[7:0] — Data Direction Register E Bits
These read/write bits control port E data direction. Reset clears
DDRE[7:0], configuring all port E pins as inputs.
1 = Corresponding port E pin configured as output
0 = Corresponding port E pin configured as input
NOTE: Avoid glitches on port E pins by writing to the port E data register before
changing data direction register E bits from 0 to 1.
Figure 19-15 shows the port E I/O logic.
READ DDRE ($000C)
WRITE DDRE ($000C)
RESET
WRITE PTE ($0008)
READ PTE ($0008)
DDREx
PTEx
Figure 19-15. Port E I/O Circuit
PTEx
Technical Data
310
MC68HC08AZ32A — Rev 1.0
I/O Ports
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