Device Architecture
tCYC
WCLK
tWCKFF
FF
tCKAF
AFF
WA/RA
NO MATCH
NO MATCH
Dist = AFF_TH
MATCH (FULL)
(Address Counter)
Figure 2-61 • FIFO FULL and AFULL Flag Assertion
WCLK
MATCH
(EMPTY)
WA/RA
NO MATCH
NO MATCH
NO MATCH
NO MATCH
Dist = AEF_TH + 1
(Address Counter)
1st rising
2nd rising
edge
after 1st
write
edge
after 1st
write
RCLK
EF
t
RCKEF
t
CKAF
AEF
Figure 2-62 • FIFO EMPTY Flag and AEMPTY Flag Deassertion
RCLK
WA/RA
(Address Counter) MATCH (FULL)
NO MATCH
NO MATCH
NO MATCH
NO MATCH
Dist = AFF_TH - 1
1st Rising
1st Rising
Edge
After 1st
Read
Edge
After 2nd
Read
WCLK
FF
tWCKF
tCKAF
AFF
Figure 2-63 • FIFO FULL Flag and AFULL Flag Deassertion
2-78
Preliminary v1.7
ACTEL [ Actel Corporation ]
