Datasheet

Figure 35-3. SPI Transfer Modes
Bit 1
Bit 6
LSB
MSB
Mode 0
SAMPLE I
MOSI/MISO
CHANGE 0
MOSI PIN
CHANGE 0
MISO PIN
Mode 2
SS
MSB
LSB
Bit 6
Bit 1
Bit 5
Bit 2
Bit 4
Bit 3
Bit 3
Bit 4
Bit 2
Bit 5
MSB first (DORD = 0)
LSB first (DORD = 1)
Mode 1
SAMPLE I
MOSI/MISO
CHANGE 0
MOSI PIN
CHANGE 0
MISO PIN
Mode 3
SS
MSB
LSB
Bit 6
Bit 1
Bit 5
Bit 2
Bit 4
Bit 3
Bit 3
Bit 4
Bit 2
Bit 5
Bit 1
Bit 6
LSB
MSB
MSB first (DORD = 0)
LSB first (DORD = 1)
35.6.2.6 Transferring Data
35.6.2.6.1 Master
In Master mode (CTRLA.MODE=0x3), when Master Slave Enable Select (CTRLB.MSSEN) is ‘1’,
hardware will control the SS line.
When Master Slave Select Enable (CTRLB.MSSEN) is '0', the SS line must be configured as an output.
SS can be assigned to any general purpose I/O pin. When the SPI is ready for a data transaction,
software must pull the SS line low.
When writing a character to the Data register (DATA), the character will be transferred to the Shift
register. Once the content of TxDATA has been transferred to the Shift register, the Data Register Empty
flag in the Interrupt Flag Status and Clear register (INTFLAG.DRE) will be set. And a new character can
be written to DATA.
Each time one character is shifted out from the master, another character will be shifted in from the slave
simultaneously. If the receiver is enabled (CTRLA.RXEN=1), the contents of the Shift register will be
SAM D5x/E5x Family Data Sheet
SERCOM SPI – SERCOM Serial Peripheral Interface
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 975