Write to SPIDAT1
SPIx_CLK
SPIx_SIMO
SPIx_SOMI
SPIx_SCS[n]
SPIx_CLK
SPIx_SOMI
SPIx_SIMO
Slave
(MASTER = 0; CLKMOD = 0)
SPIx_CLK
SPIx_SOMI
SPIx_SIMO
Master
(MASTER = 1; CLKMOD = 1)
SPIBUF
SPIDAT1
CPU/DMA
write
CPU/DMA
read
SPIDAT1
SPIBUF
CPU/DMA
read
CPU/DMA
write
SPIx_SCS[n]
SPIx_SCS[n]
Architecture
1422
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Serial Peripheral Interface (SPI)
Figure 29-3. SPI 4-Pin Option with SPIx_SCS[n]
NOTE:
During an SPI transfer, if the slave mode SPI detects a deassertion of its chip select even
before its internal character length counter overflows, then it 3-states its SPIx_SOMI pin.
Once this condition has occurred, if a SPIx_CLK edge is detected while the chip select is
deasserted, the SPI stops the transfer and sets an error flag DLENERR (data length) and
generates an interrupt if enabled.