Atmel SAM4L Xplained Pro Evaluation Kit Atmel ATSAM4L-XPRO ATSAM4L-XPRO Data Sheet

42023E–SAM–07/2013

Figure 26-6. Master Mode Flow Diagram

SPI Enable

CSAAT ?

PS ?

1

0

0

1

1

NPCS = TDR(PCS)

NPCS = MR(PCS)

Delay DLYBS

Serializer = TDR(TD)

TDRE = 1

Data Transfer

RDR(RD) = Serializer

RDRF = 1

TDRE ?

NPCS = 0xF

Delay DLYBCS

Fixed

 peripheral

Variable 

peripheral

Delay DLYBCT

0

1

CSAAT ?

0

TDRE ?

1

0

PS ?

0

1

TDR(PCS)

= NPCS ?

no

yes

MR(PCS)

= NPCS ?

no

NPCS = 0xF

Delay DLYBCS

NPCS = TDR(PCS)

NPCS = 0xF

Delay DLYBCS

NPCS = MR(PCS),

                TDR(PCS) 

Fixed

 peripheral

Variable 

peripheral

- NPCS defines the current Chip Select
- CSAAT, DLYBS, DLYBCT refer to the fields of the 
  Chip Select Register corresponding to the Current Chip Select
- When NPCS is 0xF, CSAAT is 0.