Overview
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Overview
The SPI is a high-speed synchronous serial input/output port that allows a
serial bit stream of programmed length (3 to 16 bits) to be shifted into and out
of the device at a programmed bit-transfer rate. The SPI is normally used for
communication between the microcontroller and external peripherals or
another microcontroller. Typical applications include interface to external I/O
or peripheral expansion via devices such as shift registers, display drivers,
and analog-to-digital converters.
The SPI is available with three, four or five pins. The pins SPICLK, SPISIMO
and SPISOMI are used in all SPI pin modes. The pins SPIENA and SPISCS
are optional and may be used if the pin are present on a given device.
The SPI has the following attributes:
❏
16-bit shift register
❏
Receive buffer register
❏
8-bit baud clock generator
❏
Serial clock (SPICLK) I/O pin
❏
Slave in, master out (SPISIMO) I/O pin
❏
Slave out, master in (SPISOMI) I/O pin
❏
SPI enable (SPIENA) I/O pin (4-or 5-pin mode only)
❏
Slave chip select (SPISCS) I/O pin (4- or 5-pin mode only)
The SPI allows software to program the following options:
❏
SPISOMI/SPISIMO pin direction configuration
❏
SPICLK pin source (external/internal)
❏
SPICLK frequency (interface clock [ICLK] /2 through /256)
❏
SPI pins as functional or digital I/O pins
❏
Character length (3 to 16 bits)
❏
Phase (delay/no delay)
❏
Polarity (high or low).
Note: Maximum Input Frequency
The maximum input frequency on the SPICLK pin when in slave mode is the
ICLK frequency /2.
Summary of Contents for TMS470R1 series
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