MC68HC08AZ32A Datasheet, PDF (163/312 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Port E
13.6 Port E
Port E is an 8-bit special function port that shares two of its pins with the TIMA, two of its pins with the
serial communications interface module (SCI), and four of its pins with the serial peripheral interface
module (SPI).
13.6.1 Port E Data Register (PTE)
The port E data register contains a data latch for each of the eight port E pins.
Address: $0008
Bit 7
Read:
PTE7
Write:
Reset:
Alternative Functions: SPSCK
6
PTE6
MOSI
5
PTE5
MISO
4
3
PTE4
PTE3
Unaffected by reset
SS
TACH1
2
PTE2
TACH0
1
PTE1
RxD
Bit 0
PTE0
TxD
Figure 13-14. Port E Data Register (PTE)
PTE[7:0] — Port E Data Bits
PTE[7:0] are read/write, software programmable bits. Data direction of each port E pin is under the
control of the corresponding bit in data direction register E.
SPSCK — SPI Serial Clock
The PTE7/SPSCK pin is the serial clock input of a SPI slave module and serial clock output of a SPI
master modules. When the SPE bit is clear, the PTE7/SPSCK pin is available for general-purpose I/O.
MOSI — Master Out/Slave In
The PTE6/MOSI pin is the master out/slave in terminal of the SPI module. When the SPE bit is clear,
the PTE6/MOSI pin is available for general-purpose I/O. See 16.12.1 SPI Control Register (SPCR).
MISO — Master In/Slave Out
The PTE5/MISO pin is the master in/slave out terminal of the SPI module. When the SPI enable bit,
SPE, is clear, the SPI module is disabled, and the PTE5/MISO pin is available for general-purpose I/O.
See 16.12.1 SPI Control Register (SPCR).
SS — Slave Select
The PTE4/SS pin is the slave select input of the SPI module. When the SPE bit is clear, or when the
SPI master bit, SPMSTR, is set and MODFEN bit is low, the PTE4/SS pin is available for
general-purpose I/O. See 16.12.1 SPI Control Register (SPCR). When the SPI is enabled as a slave,
the DDRF0 bit in data direction register E (DDRE) has no effect on the PTE4/SS pin.
NOTE
Data direction register E (DDRE) does not affect the data direction of port
E pins that are being used by the SPI 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 13-5.
MC68HC08AZ32A Data Sheet, Rev. 2
Freescale Semiconductor
163