AT32F425
Series Reference Manual
2022.03.30
Page 163
Ver 2.01
Programmable clock plarity and phase
Programmable data transfer order (MSB-first or LSB-first)
Programmable error interrupt flags (CS pulse error, receiver overflow error, master mode error
and CRC error)
Programmable transmit data buffer empty interrupt and receive data buffer full interrupt
Support transmission and reception using DMA
Support hardware CRC transmission and error checking
Busy status flag
Compatible with the TI protocol
13.2.2 Full-duplex/half-duplex selector
When used as an SPI interface, it supports four synchronous modes: two-wire unidirectional full-duplex,
single-wire unidirectional receive only, single-wire bidirectional half-duplex transmit and single-wire
bidirectional half-duplex receive.
Figure 13-2 shows the two-wire unidirectional full-duplex mode and SPI IO connection:
The SPI operats in two-wire unidirectional full-duplex mode when the SLBEN bit and the ORA bit is both
0. In this case, the SPI supports data transmission and reception at the same time. IO connection is as
follows:
Figure 13-2 SPI two-wire unidirectional full-duplex connection
SPI master
SCK
MISO
MOSI
CS
SPI slave
SCK
MISO
MOSI
CS
In either master or slave mode, it is required to wait until the RDBF bit and TDBE bit is set, and BF=0
before disabling the SPI or entering power-saving mode (or disabling SPI system clock).
Figure 13-3 shows the single-wire unidirectional receive-only mode and SPI IO connection
The SPI operates in single-wire unidirectional receive-only mode when the SLBEN is 0 and the ORA is
set. In this case, the SPI can be used only for data reception (transmission is not supported). The MISO
pin transmits data in slave mode and receives data in master mode. The MOSI pin transmits data in
master mode and receives data in salve mode.