Datasheet

Port E
MC68HC908GR16 Data Sheet, Rev. 5.0
Freescale Semiconductor 133
12.6 Port E
Port E is a 6-bit special-function port that shares two of its pins with the enhanced serial communications
interface (ESCI) module.
12.6.1 Port E Data Register
The port E data register contains a data latch for each of the six port E pins.
PTE5–PTE0 — Port E Data Bits
These read/write bits are software-programmable. Data direction of each port E pin is under the control
of the corresponding bit in data direction register E. Reset has no effect on port E data.
NOTE
Data direction register E (DDRE) does not affect the data direction of port
E pins that are being used by the ESCI module. However, the DDRE bits
always determine whether reading port E returns the states of the latches
or the states of the pins. See Table 12-6.
RxD — SCI Receive Data Input
The PTE1/RxD pin is the receive data input for the ESCI module. When the enable SCI bit, ENSCI, is
clear, the ESCI module is disabled, and the PTE1/RxD pin is available for general-purpose I/O. See
Chapter 14 Enhanced Serial Communications Interface (ESCI) Module.
TxD — SCI Transmit Data Output
The PTE0/TxD pin is the transmit data output for the ESCI module. When the enable SCI bit, ENSCI,
is clear, the ESCI module is disabled, and the PTE0/TxD pin is available for general-purpose I/O. See
Chapter 14 Enhanced Serial Communications Interface (ESCI) Module.
Address: $0008
Bit 7654321Bit 0
Read: 0 0
PTE5 PTE4 PTE3 PTE2 PTE1 PTE0
Write:
Reset: Unaffected by reset
Alternative
Function:
RxD TxD
= Unimplemented
Figure 12-17. Port E Data Register (PTE)