MC68HC08AS32 Datasheet, PDF (149/280 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

11.6 Port E
Port E is an 8-bit special-function port that shares two of its pins with the timer
interface module (TIM), two of its pins with the serial communications interface
module (SCI), and four of its pins with the serial peripheral interface module (SPI).
11.6.1 Port E Data Register
The port E data register contains a data latch for each of the eight port E pins.
Address:
Read:
Write:
Reset:
Alternate
Function:
$0008
Bit 7
PTE7
SPSCK
6
PTE6
MOSI
5
PTE5
MISO
4
3
PTE4
PTE3
Unaffected by reset
SS
TCH1
2
PTE2
TCH0
1
PTE1
RxD
Bit 0
PTE0
TxD
Figure 11-14. Port E Data Register (PTE)
NOTE:
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 Bit
The PTE7/SPSCK pin is the serial clock input of an SPI slave module and serial
clock output of an SPI master module. When the SPE bit is clear, the
PTE7/SPSCK pin is available for general-purpose I/O.
MOSI — Master Out/Slave In Bit
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 14.13.1 SPI Control Register.)
MISO — Master In/Slave Out Bit
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 14.13.1 SPI Control
Register.)
SS — Slave Select Bit
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 14.12.4 SS (Slave
Select).) When the SPI is enabled as a slave, the DDRE4 bit in data direction
register E (DDRE) has no effect on the PTE4/SS pin.
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
MC68HC08AS32 — Rev. 4.1
Freescale Semiconductor
Data Sheet
149