Sony CXD5602 User Manual page 925


In the case that "failure" has been retuned as a result of exclusive access, write to the slave has not been
performed.
Success case of exclusive access

The snooping is released after an exclusive write (ExW) is issued from the master obtaining exclusive access
right to the target address to snoop. At this time, if exclusion process to the target address to snoop has been
successful, "success" will be returned. (refer to Figure APP-111)

An exclusive read access always receives "success" response. That is, "success" is returned even during one
exclusive read access's snooping, another exclusive read access has occurred. After the other exclusive read
access's occurrence, "success" is returned to the exclusive write access to the target address to snoop, issued
from the master obtaining exclusive access right. (refer to Figure APP-112)
Access phase
Respons phase
snoop_mid
snoop_addr
snoop_flag
exfail_flag
Access phase
Respons phase
snoop_mid
snoop_addr
snoop_flag
exfail_flag
Failure case of exclusive access

In the case that a usual write access (not an exclusive write access) occurs to a target address to snoop,
exclusive access processing is failed and the exclusive write access is blocked.
"Failure" will be returned at the timing of an exclusive write access from the master with the exclusive
access right. (refer to Figure APP-113)

In the case that an exclusive write access (ExW) occurs from the master without the exclusive access right to
ExR
A0
MID0
D0
success
Figure APP-111 Success Case 1 of Exclusive Access
ExR
A0
MID0
D0
success
Figure APP-112 Success Case 2 of Exclusive Access
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MID0
A0
ExR
A1
MID0
D0
success
MID0
A0
CXD5602 User Manual
ExW
A0
MID0
D1
success
ExW
A0
MID0
D1
success