Datasheet

127
SAM9261 [DATASHEET]
Atmel-6062O-ATARM-SAM9261-Datasheet_21-Jun-16
18.5.2 Bus Matrix Slave Configuration Registers
Name: MATRIX_SCFG0...MATRIX_SCFG4
Address: 0xFFFFEE04
Access: Read/Write
• SLOT_CYCLE: Maximum Number of Allowed Cycles for a Burst
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 set to avoid locking very slow slaves when very long bursts are used.
This limit should not be very small. An unreasonably small value breaks every burst and the Bus Matrix spends its time
arbitrating without performing any data transfer. 16 cycles is a reasonable value for SLOT_CYCLE.
• DEFMASTR_TYPE: Default Master Type
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 one cycle latency for the first transfer of a burst.
1: Last Default Master
At the end of the current slave access, if no other master request is pending, the slave remains connected to the last mas-
ter that accessed it.
This results in not having the one cycle latency when the last master is trying 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 with the fixed master that
has its index in FIXED_DEFMSTR.
This results in not having the one cycle latency when the fixed master is trying to access the slave again.
• FIXED_DEFMSTR: Fixed Index of Default Master
This is the index of the Fixed Default Master for this slave.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
– – – FIXED_DEFMSTR DEFMSTR_TYPE
15 14 13 12 11 10 9 8
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76543210
SLOT_CYCLE