Freescale Semiconductor MC68HC908MR32 - Manual (Page 195)

MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
Freescale Semiconductor 195
Chapter 15
Serial Peripheral Interface Module (SPI)
15.1 Introduction
The serial peripheral interface (SPI) module allows full-duplex, synchronous, serial communications with
peripheral devices.
15.2 Features
Features of the SPI module include:
• Full-duplex operation
• Master and slave modes
• Double-buffered operation with separate transmit and receive registers
• Four master mode frequencies (maximum = bus frequency
÷ 2)
• Maximum slave mode frequency = bus frequency
• Serial clock with programmable polarity and phase
• Two separately enabled interrupts with central processor unit (CPU) service:
–
SPRF (SPI receiver full)
– SPTE (SPI transmitter empty)
• Mode fault error flag with CPU interrupt capability
• Overflow error flag with CPU interrupt capability
• Programmable wired-OR mode
• I
2
C (inter-integrated circuit) compatibility
15.3 Pin Name Conventions
The generic names of the SPI input/output (I/O) pins are:
• SS, slave select
• SPSCK, SPI serial clock
• MOSI, master out/slave in
• MISO, master in/slave out
SPI pins are shared by parallel I/O ports or have alternate functions. The full name of an SPI pin reflects
the name of the shared port pin or the name of an alternate pin function. The generic pin names appear
in the text that follows.
Table 15-1 shows the full names of the SPI I/O pins.
Table 15-1. Pin Name Conventions
Generic Pin Names: MISO MOSI SPSCK SS
Full Pin Names: PTF3/MISO PTF2/MOSI PTF0/SPSCK PTF1/SS