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INTERVAL MODE SERIAL PERIPHERAL INTERFACE
The interval mode serial peripheral interface (ISPI) module provides a high-speed
synchronous serial interface to communicate to external devices such as A/D con-
verters and non-volatile RAMs. The ISPI provides the control and clock for data trans-
fers and can be configured as either a master or a slave device. In addition, the ISPI
includes a timer that delays the initiation of a serial transfer for a programmable
period.
12.1 Overview
The ISPI transfers data between the MMC2001 and a peripheral device over a serial
link. Enable and clock signals are used to exchange data between the two devices. If
the external device is a transmit-only device (e.g., an A/D converter), the ISPI output
port can be ignored or used for other purposes. Figure 12-1 shows a block diagram
of the ISPI.
ISPI Interval
Module
Interface
SPI_IRQ
12.2 Operation
The ISPI provides three operating modes. Manual mode is a traditional SPI master
operation mode. Interval mode is similar to manual mode, except that it includes a
programmable timer to support timed transfers. Interval mode is suitable for control-
ling an external sound DAC, for example.
MMC2001
REFERENCE MANUAL
Freescale Semiconductor, Inc.
SECTION 12
Baud
Bit
Control
Figure 12-1 ISPI Channel Block Diagram
INTERVAL MODE SERIAL PERIPHERAL INTERFACE
For More Information On This Product,
Go to: www.freescale.com
State
Shift
Rx
Tx
SPI_CLK
SPI_MISO
SPI_MOSI
SPI_EN
SPI_GP
MOTOROLA
12-1
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