
General Description
M68HC11E Family Data Sheet, Rev. 5.1
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Freescale Semiconductor
1.4.15 Port D
Pins PD5–PD0 can be used for general-purpose I/O signals. These pins alternately serve as the serial
communication interface (SCI) and serial peripheral interface (SPI) signals when those subsystems are
enabled.
PD0 is the receive data input (RxD) signal for the SCI.
PD1 is the transmit data output (TxD) signal for the SCI.
PD5–PD2 are dedicated to the SPI:
–
PD2 is the master in/slave out (MISO) signal.
–
PD3 is the master out/slave in (MOSI) signal.
–
PD4 is the serial clock (SCK) signal.
–
PD5 is the slave select (SS) input.
1.4.16 Port E
Use port E for general-purpose or analog-to-digital (A/D) inputs.
CAUTION
If high accuracy is required for A/D conversions, avoid reading port E during
sampling, as small disturbances can reduce the accuracy of that result.