Enhanced SPI Module Overview
985
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Serial Peripheral Interface (SPI)
12.1.2 SPI Module Signal Summary
Table 12-1. SPI Module Signal Summary
Signal Name
Description
External Signals
SPICLK
SPI clock
SPISIMO
SPI slave in, master out
SPISOMI
SPI slave out, master in
SPISTE
SPI slave transmit enable
Control
SPI Clock Rate
LSPCLK
Interrupt signals
SPIRXINT
Transmit interrupt/ Receive Interrupt in non FIFO mode (referred to as SPI INT)
Receive in interrupt in FIFO mode
SPITXINT
Transmit interrupt – FIFO
12.1.3 Overview of SPI Module Registers
The SPI port operation is configured and controlled by the registers listed in
Table 12-2. SPI Registers
Name
Address Range
Size (x16)
Description
SPICCR
0x0000-7040
1
SPI Configuration Control Register
SPICTL
0x0000-7041
1
SPI Operation Control Register
SPIST
0x0000-7042
1
SPI Status Register
SPIBRR
0x0000-7044
1
SPI Baud Rate Register
SPIEMU
0x0000-7046
1
SPI Emulation Buffer Register
SPIRXBUF
0x0000-7047
1
SPI Serial Input Buffer Register
SPITXBUF
0x0000-7048
1
SPI Serial Output Buffer Register
SPIDAT
0x0000-7049
1
SPI Serial Data Register
SPIFFTX
0x0000-704A
1
SPI FIFO Transmit Register
SPIFFRX
0x0000-704B
1
SPI FIFO Receive Register
SPIFFCT
0x0000-704C
1
SPI FIFO Control Register
SPIPRI
0x0000-704F
1
SPI Priority Control Register
This SPI has 16-bit transmit and receive capability, with double-buffered transmit and double-buffered
receive. All data registers are 16-bits wide.
The SPI is no longer limited to a maximum transmission rate of LSPCLK/8 in slave mode. The maximum
transmission rate in both slave mode and master mode is now LSPCLK/4.
Writes of transmit data to the serial data register, SPIDAT (and the new transmit buffer, SPITXBUF), must
be left-justified within a 16-bit register.
The control and data bits for general-purpose bit I/O multiplexing have been removed from this peripheral,
along with the associated registers, SPIPC1 (704Dh) and SPIPC2 (704Eh). These bits are now in the
General-Purpose I/O registers.
Twelve registers inside the SPI module control the SPI operations:
•
SPICCR (SPI configuration control register). Contains control bits used for SPI configuration
–
SPI module software reset
–
SPICLK polarity selection
–
Four SPI character-length control bits