RX610 Group
11. Buses
R01UH0032EJ0120 Rev.1.20
Page 266 of 1006
Feb 20, 2013
RRCV[3:0] Bits (Read Recovery)
These bits specify the number of recovery cycles to be inserted after a read access to the external bus.
When a value except 0000b is written to these bits, one to 15 recovery cycles are inserted in the following cases.
•
When a write access is made to the external bus after a read access to the external bus
(Recovery cycles are also inserted when consecutive accesses are made in the same area.)
•
When a read access is made to another area after a read access to the external bus
(No recovery cycle is inserted when consecutive accesses are made in the same area.)
WRCV[3:0] Bits (Write Recovery)
These bits specify the number of recovery cycles to be inserted after a write access to the external bus.
When a value except 0000b is written to these bits, one to 15 recovery cycles are inserted in the following cases.
•
When a read access is made to the external bus after a write access to the external bus
(Recovery cycles are also inserted when consecutive accesses are made in the same area.)
No recovery cycle is inserted during a write access after a write access.
Table 11.7 Insertion of Recovery Cycles
Access Type
External Address
Space
Insertion of Recovery Cycles
Read access after write access
Same area
Recovery cycles specified by the WRCV[3:0] bits are inserted.
Different area
Recovery cycles specified by the WRCV[3:0] bits are inserted.
Write access after write access
Same area
No recovery cycle is inserted.
Different area
No recovery cycle is inserted.
Write access after read access
Same area
Recovery cycles specified by the RRCV[3:0] bits are inserted.
Different area
Recovery cycles specified by the RRCV[3:0] bits are inserted.
Read access after read access
Same area
No recovery cycle is inserted.
Different area
Recovery cycles specified by the RRCV[3:0] bits are inserted.