MC68HC05F8 Datasheet, PDF (65/126 Pages) Motorola, Inc – High-density complementary metal oxide semiconductor(HCMOS) microcontroller unit

Freescale Semiconductor, Inc.
7
SERIAL PERIPHERAL INTERFACE
The serial peripheral interface (SPI) is an interface built into the MC68HC05F8 MCU which allows
two MC68HC05F8 MCUs to be interconnected within a single “black box” or on the same printed
circuit board. In a serial peripheral interface (SPI), separate wires (signals) are required for data
and clock. In the SPI format, the clock is not included in the data stream and must be furnished
as a separate signal. An SPI system may be configured in one containing one master and one
slave MCUs.
Figure 7-1 illustrates a normal system configurations. In this system three basic lines (signals) are
required for the Serial Clock (SCK), Serial Data Input (SDI), and Serial Data Output (SDO) lines.
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7.1
Features
• Full duplex, three-wire synchronous transfer
• Master or slave operation
• 447.5 KHz master bit frequency
• 1.79MHz (Max.) slave bit frequency
• End of transmission interrupt flag
• Data collision flag protection
7.2
Signal Description
The three basic signals (SCK, SDO and SDI) are described in the following paragraphs. Each
signal function is described for both the master and slave mode. Figure 7-2 summarizes the SPI
port timing for data exchange operation.
MC68HC05F8
SERIAL PERIPHERAL INTERFACE
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7-1