MC68HC908JW32_09 Datasheet, PDF (127/232 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Chapter 10
Serial Peripheral Interface Module (SPI)
10.1 Introduction
This section describes the serial peripheral interface (SPI) module, which allows full-duplex,
synchronous, serial communications with peripheral devices.
10.2 Features
Features of the SPI module include the following:
• 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:
– 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
10.3 Pin Name Conventions and I/O Register Addresses
The text that follows describes the SPI. The SPI I/O pin names are SS (slave select), SPSCK (SPI serial
clock), CGND (clock ground), MOSI (master out slave in), and MISO (master in/slave out). The SPI
shares four I/O pins with four parallel I/O ports.
The full names of the SPI I/O pins are shown in Table 10-1. The generic pin names appear in the text that
follows.
Table 10-1. Pin Name Conventions
SPI Generic
Pin Names:
MISO
Full SPI
Pin Names:
SPI
PTE6/MISO
MOSI
PTE5/MOSI
SS
PTE7/SS
SPSCK
PTE4/SPSCK
CGND
V_SS
Figure 10-1 summarizes the SPI I/O registers.
MC68HC908JW32 Data Sheet, Rev. 6
Freescale Semiconductor
127