MC68HC08AB16A Datasheet, PDF (320/380 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Input/Output (I/O) Ports
17.7.2 Data Direction Register E (DDRE)
Data direction register E determines whether each port E pin is an input
or an output. Writing a logic 1 to a DDRE bit enables the output buffer for
the corresponding port E pin; a logic 0 disables the output buffer.
Address: $000C
Bit 7
6
5
4
3
2
1
Read:
DDRE7 DDRE6 DDRE5 DDRE4 DDRE3 DDRE2 DDRE1
Write:
Reset: 0
0
0
0
0
0
0
Figure 17-16. Data Direction Register E (DDRE)
Bit 0
DDRE0
0
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 17-17 shows
the port E I/O logic.
READ DDRE ($000C)
WRITE DDRE ($000C)
RESET
WRITE PTE ($0008)
DDREx
PTEx
PTEx
READ PTE ($0008)
Figure 17-17. Port E I/O Circuit
Technical Data
320
MC68HC08AB16A — Rev. 2.0
Input/Output (I/O) Ports
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