ADV
ANCEINFORMA
TION
SPISIMO
SPISOMI
SPICLK
SPISTE
SPI
Low Speed
Prescaler
DMA
PIE
LSPCLK
SYSCLK
SYSRS
SPIINT
SPITXINT
SPIRXDMA
SPITXDMA
P
e
ri
p
h
e
ra
l
B
u
s
CPU
PCLKCR8
GPIO
MUX
Bit
Clock
TMS320F28377S, TMS320F28376S, TMS320F28375S, TMS320F28374S
SPRS881A – AUGUST 2014 – REVISED JUNE 2015
The SPI operates in master or slave mode. The master initiates data transfer by sending the SPICLK
signal. For both the slave and the master, data is shifted out of the shift registers on one edge of the
SPICLK and latched into the shift register on the opposite SPICLK clock edge. If the CLOCK PHASE bit
(SPICTL.3) is high, data is transmitted and received a half-cycle before the SPICLK transition. As a result,
both controllers send and receive data simultaneously. The application software determines whether the
data is meaningful or dummy data. There are three possible methods for data transmission:
•
Master sends data; slave sends dummy data
•
Master sends data; slave sends data
•
Master sends dummy data; slave sends data
The master can initiate a data transfer at any time because it controls the SPICLK signal. The software,
however, determines how the master detects when the slave is ready to broadcast data.
Figure 5-57. SPI
142
Specifications
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