Parallel Input/Output (I/O) Ports
Port E
M68HC11E Family — Rev. 5
Data Sheet
MOTOROLA
Parallel Input/Output (I/O) Ports
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113
Bits [7:6] — Unimplemented
Always read 0
DDRD[5:0] — Port D Data Direction Bits
When DDRD bit 5 is 1 and MSTR = 1 in SPCR, PD5/SS is a general-purpose
output and mode fault logic is disabled.
0 = Input
1 = Output
6.6 Port E
Port E is used for general-purpose static inputs or pins that share functions with the
analog-to-digital (A/D) converter system. When some port E pins are being used
for general-purpose input and others are being used as A/D inputs, PORTE should
not be read during the sample portion of an A/D conversion.
6.7 Handshake Protocol
Simple and full handshake input and output functions are available on ports B and
C pins in single-chip mode. In simple strobed mode, port B is a strobed output port
and port C is a latching input port. The two activities are available simultaneously.
The STRB output is pulsed for two E-clock periods each time there is a write to the
PORTB register. The INVB bit in the PIOC register controls the polarity of STRB
pulses. Port C levels are latched into the alternate port C latch (PORTCL) register
on each assertion of the STRA input. STRA edge select, flag, and interrupt enable
bits are located in the PIOC register. Any or all of the port C lines can still be used
as general-purpose I/O while in strobed input mode.
Address:
$1009
Bit 7
6
5
4
3
2
1
Bit 0
Read:
DDRD5
DDRD4
DDRD3
DDRD2
DDRD1
DDRD0
Write:
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 6-8. Port D Data Direction Register (DDRD)
Address:
$100A
Bit 7
6
5
4
3
2
1
Bit 0
Read:
PE7
PE6
PE5
PE4
PE3
PE2
PE1
PE0
Write:
Reset:
Indeterminate after reset
Alternate Function:
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
Figure 6-9. Port E Data Register (PORTE)
F
Freescale Semiconductor, Inc.
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