Freescale Semiconductor HCS08 Series, Справочное руководство

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MC9S08JS16 MCU Series Reference Manual, Rev. 4
Freescale Semiconductor 187
Chapter 13
16-Bit Serial Peripheral Interface (S08SPI16V1)
13.1 Introduction
The 8- or 16-bit selectable serial peripheral interface (SPI) module provides for full-duplex, synchronous,
serial communication between the MCU and peripheral devices. These peripheral devices can include
other microcontrollers, analog-to-digital converters, shift registers, sensors, memories, etc.
The SPI runs at a baud rate up to the bus clock divided by two in master mode and up to the bus clock
divided by four in slave mode. Software can poll the status flags, or SPI operation can be interrupt driven.
The SPI also supports a data length of 8 or 16 bits and provides a hardware match feature for the receive
data buffer.
The MC9S08JS16 series have one serial peripheral interface module (SPI). The four pins associated with
SPI functionality are shared with PTA[4:1] See “MC9S08JS16 Series
Data Sheet ,” for SPI electrical
parametric information.
13.1.1 SPI Port Configuration Information
To configure the SPI for high speed operation (operating frequency of greater than 6 MHz), the input filters
on the SPI port pins must be disabled by clearing the SPIFE in SOPT2. Doing so allows data transfers to
occur at the higher frequency but at a risk of introducing noise during data transfers. If running the SPI at
a baud rate of 8 MHz or greater, the application must enable the high output drive strength selection on the
port pins corresponding to the affected SPI port pins.
By default, the input filters on the SPI port pins will be enabled (SPIFE=1), which restricts the SPI data
rate to 6 MHz, but protects the SPI from noise during data transfers.