mc68hc908jb8 Freescale Semiconductor, Inc, mc68hc908jb8 Datasheet - Page 215

• Manufacturer Part Number: mc68hc908jb8
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

12.7.2 Data Direction Register E
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Freescale Semiconductor
NOTE:
NOTE:
Address:
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.
DDRE[4:0] — Data Direction Register E Bits
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.
For those devices packaged in a 20-pin PDIP and 20-pin SOIC package,
PTE2 and PTE0 are not connected. DDRE2 and DDRE0 should be set
to a 1 to configure PTE2 and PTE0 as outputs.
Figure 12-16
Reset:
Read:
Write:
These read/write bits control port E data direction. Reset clears
DDRE[4:0], configuring all port E pins as inputs.
PTE4 and PTE3 pins are open-drain when configured as output.
1 = Corresponding port E pin configured as output
0 = Corresponding port E pin configured as input
$0009
Bit 7
Figure 12-15. Data Direction Register E (DDRE)
0
0
shows the port E I/O circuit logic.
Input/Output Ports (I/O)
= Unimplemented
6
0
0
0
5
0
DDRE4
0
4
DDRE3
3
0
DDRE2
2
0
Input/Output Ports (I/O)
DDRE1
1
0
Technical Data
DDRE0
Bit 0
Port E
0
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