CY7C024/0241
CY7C025/0251
Document #: 38-06035 Rev. *C
Page 6 of 21
Table 2. Interrupt Operation Example (Assumes BUSYL=BUSYR=HIGH)[6]
Function
Left Port
Right Port
R/WL
CEL
OEL
A0L–11L
INTL R/WR CER
OER
A0R–11R
INTR
Set Right INTR Flag
L
L
X
(1)FFF
X
X
X
X
X
L[8]
Reset Right INTR Flag
X
X
X
X
X
X
L
L
(1)FFF
H[7]
Set Left INTL Flag
X
X
X
X
L[7]
LL
X
(1)FFE
X
Reset Left INTL Flag
X
L
L
(1)FFE
H[8]
XX
X
X
X
Table 3. Semaphore Operation Example
Function
I/O0–I/O15/17
Left
I/O0–I/O15/17
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:
6. A0L–12L and A0R–12R, 1FFF/1FFE for the CY7C025.
7. If BUSYR=L, then no change.
8. If BUSYL=L, then no change.