SM320LF2407-EP Datasheet, PDF (41/112 Pages) Texas Instruments – 
DSP CONTROLLERS

SM320LF2407AĆEP
DSP CONTROLLERS
SGUS036B − JULY 2003 − REVISED OCTOBER 2003
serial peripheral interface (SPI) module
Some 240xA devices include the four-pin serial peripheral interface (SPI) module. The SPI is a high-speed,
synchronous serial I/O port that allows a serial bit stream of programmed length (one to sixteen bits) to be shifted
into and out of the device at a programmable bit-transfer rate. Normally, the SPI is used for communications
between the DSP controller and external peripherals or another processor. Typical applications include external
I/O or peripheral expansion through devices such as shift registers, display drivers, and ADCs. Multidevice
communications are supported by the master/slave operation of the SPI.
The SPI module features include:
D Four external pins:
− SPISOMI: SPI slave-output/master-input pin
− SPISIMO: SPI slave-input/master-output pin
− SPISTE: SPI slave transmit-enable pin
− SPICLK: SPI serial-clock pin
NOTE: All four pins can be used as GPIO, if the SPI module is not used.
D Two operational modes: master and slave
D Baud rate: 125 different programmable rates / 10 Mbps at 40-MHz CPUCLK
D Data word length: one to sixteen data bits
D Four clocking schemes (controlled by clock polarity and clock phase bits) include:
− Falling edge without phase delay: SPICLK active high. SPI transmits data on the falling edge of the
SPICLK signal and receives data on the rising edge of the SPICLK signal.
− Falling edge with phase delay: SPICLK active high. SPI transmits data one half-cycle ahead of the
falling edge of the SPICLK signal and receives data on the falling edge of the SPICLK signal.
− Rising edge without phase delay: SPICLK inactive low. SPI transmits data on the rising edge of the
SPICLK signal and receives data on the falling edge of the SPICLK signal.
− Rising edge with phase delay: SPICLK inactive low. SPI transmits data one half-cycle ahead of the
falling edge of the SPICLK signal and receives data on the rising edge of the SPICLK signal.
D Simultaneous receive and transmit operation (transmit function can be disabled in software)
D Transmitter and receiver operations are accomplished through either interrupt-driven or polled algorithms.
D Nine SPI module control registers: Located in control register frame beginning at address 7040h.
NOTE: All registers in this module are 16-bit registers that are connected to the 16-bit peripheral bus. When a register is accessed, the
register data is in the lower byte (7 −0), and the upper byte (15 −8) is read as zeros. Writing to the upper byte has no effect.
• POST OFFICE BOX 1443 HOUSTON, TEXAS 77251−1443
41