Atmel SAM4L-EK Atmel ATSAM4L-EK ATSAM4L-EK Data Sheet

42023E–SAM–07/2013

shows a block diagram of the SPI when operating in master mode. 

 shows a flow chart describing how transfers are handled.

Figure 26-5. Master Mode Block Diagram

Baud Rate Generator

RXFIFOEN

4 – Character FIFO

Shift Register

TDRE

RXFIFOEN

4 – Character FIFO

PS

PCSDEC

Current 

Peripheral

MODF

MODFDIS

MSTR

SCBR

CSR0..3

CSR0..3

CPOL

NCPHA

BITS

RDR

RD

RDRF

OVRES

TD

TDR

RDR

CSAAT

CSNAAT

CSR0..3

PCS

MR

PCS

TDR

SPCK

CLK_SPI

MISO

MOSI

MSB

LSB

NPCS1

NPCS2

NPCS3

NPCS0

SPI 

Clock

0

1

0
1

0

1

NPCS0