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

42023E–SAM–07/2013

SCFG0...SCFG15

Read/Write

0x40 - 0x7C

0x00000010

•

0: Round-Robin Arbitration

1: Fixed Priority Arbitration

•

This is the number of the Default Master for this slave. Only used if DEFMSTR_TYPE is 2. Specifying the number of a master 

which is not connected to the selected slave is equivalent to setting DEFMSTR_TYPE to 0.

•

0: No Default Master

At the end of the current slave access, if no other master request is pending, the slave is disconnected from all masters.

This results in a one cycle latency for the first access of a burst transfer or for a single access.

1: Last Default Master

At the end of the current slave access, if no other master request is pending, the slave stays connected to the last master having 

accessed it.

This results in not having one cycle latency when the last master tries to access the slave again.

2: Fixed Default Master

At the end of the current slave access, if no other master request is pending, the slave connects to the fixed master the number 

that has been written in the FIXED_DEFMSTR field.

This results in not having one cycle latency when the fixed master tries to access the slave again.

•

When the SLOT_CYCLE limit is reached for a burst, it may be broken by another master trying to access this slave.

This limit has been placed to avoid locking a very slow slave when very long bursts are used.

This limit must not be very small. Unreasonably small values break every burst and the Bus Matrix arbitrates without performing 

any data transfer. 16 cycles is a reasonable value for SLOT_CYCLE.

31

30

29

28

27

26

25

24

–

–

–

–

–

–

–

ARBT

23

22

21

20

19

18

17

16

–

–

FIXED_DEFMSTR

DEFMSTR_TYPE

15

14

13

12

11

10

9

8

–

–

–

–

–

–

–

–

7

6

5

4

3

2

1

0

SLOT_CYCLE