CYDC256B16, CYDC128B16,
CYDC064B16, CYDC128B08,
CYDC064B08
Document #: 001-01638 Rev. *E
Page 8 of 26
Table 3. Input Read Register Operation[16, 19]
SFEN
CE
R/W
OE
UB
LB
ADDR
I/O0–I/O1 I/O2–I/O15
Mode
HLHL
L
L
x0000-Max VALID[17] VALID[17] Standard Memory Access
L
L
H
L
X
L
x0000
VALID[18]
X
IRR Read
Table 4. Output Drive Register [20]
SFEN
CE
R/W
OE
UB
LB
ADDR
I/O0–I/O4 I/O5–I/O15
Mode
HLH
X[21]
L[17]
L[17]
x0000-Max VALID[17] VALID[17] Standard Memory Access
LL
L
X
X
L
x0001
VALID[18]
X
ODR Write[20, 22]
LL
H
L
X
L
x0001
VALID[18]
X
ODR Read[20]
Table 5. Semaphore Operation Example
Function
I/O0–I/O15 Left I/O0–I/O15 Right
Status
No action
1
1
Semaphore-free
Left port writes 0 to semaphore
0
1
Left Port has semaphore token
Right port writes 0 to semaphore
0
1
No change. Right side has no write access to semaphore
Left port writes 1 to semaphore
1
0
Right port obtains semaphore token
Left port writes 0 to semaphore
1
0
No change. Left port has no write access to semaphore
Right port writes 1 to semaphore
0
1
Left port obtains semaphore token
Left port writes 1 to semaphore
1
1
Semaphore-free
Right port writes 0 to semaphore
1
0
Right port has semaphore token
Right port writes 1 to semaphore
1
1
Semaphore free
Left port writes 0 to semaphore
0
1
Left port has semaphore token
Left port writes 1 to semaphore
1
1
Semaphore-free
Notes:
16. SFEN = VIL for IRR reads.
17. UB or LB = VIL. If LB = VIL, then DQ<7:0> are valid. If UB = VIL then DQ<15:8> are valid.
18. LB must be active (LB = VIL) for these bits to be valid.
19. SFEN active when either CEL = VIL or CER = VIL. It is inactive when CEL = CER = VIH.
20. SFEN = VIL for ODR reads and writes.
21. Output enable must be low (OE = VIL) during reads for valid data to be output.
22. During ODR writes data will also be written to the memory.
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