CY7C024AV/025AV/026AV
CY7C0241AV/0251AV/036AV
Table 1. Non-Contending Read/Write
Inputs
CE
H
X
L
L
L
L
L
L
X
H
X
H
X
L
L
X
X
R/W
X
X
L
L
L
H
H
H
X
H
H
OE
X
X
X
X
X
L
L
L
H
L
L
X
X
X
X
UB
X
H
L
H
L
L
H
L
X
X
H
X
H
L
X
LB
X
H
H
L
L
H
L
L
X
X
H
X
H
X
L
SEM
H
H
H
H
H
H
H
H
X
L
L
L
L
L
L
I/O
9
–I/O
17
High Z
High Z
Data In
High Z
Data In
Data Out
High Z
Data Out
High Z
Data Out
Data Out
Data In
Data In
Outputs
I/O
0
–I/O
8
High Z
High Z
High Z
Data In
Data In
High Z
Data Out
Data Out
High Z
Data Out
Data Out
Data In
Data In
Operation
Deselected: Power-Down
Deselected: Power-Down
Write to Upper Byte Only
Write to Lower Byte Only
Write to Both Bytes
Read Upper Byte Only
Read Lower Byte Only
Read Both Bytes
Outputs Disabled
Read Data in Semaphore Flag
Read Data in Semaphore Flag
Write D
IN0
into Semaphore Flag
Write D
IN0
into Semaphore Flag
Not Allowed
Not Allowed
Table 2. Interrupt Operation Example (assumes BUSY
L
= BUSY
R
= HIGH)
[9]
Left Port
Function
Set Right INT
R
Flag
Reset Right INT
R
Flag
Set Left INT
L
Flag
Reset Left INT
L
Flag
R/W
L
L
X
X
X
CE
L
L
X
X
L
OE
L
X
X
X
L
A
0L–13L
FFF
[12]
X
X
1FFE
[12]
INT
L
X
X
L
[10]
H
[11]
R/W
R
X
X
L
X
CE
R
X
L
L
X
Right Port
OE
R
X
L
X
X
A
0R–13R
X
FFF (or 1/3FFF)
1FFE (or 1/3FFE)
X
INT
R
L
[11]
H
[10]
X
X
Table 3. Semaphore Operation Example
Function
No action
Left port writes 0 to semaphore
Right port writes 0 to semaphore
Left port writes 1 to semaphore
Left port writes 0 to semaphore
Right port writes 1 to semaphore
Left port writes 1 to semaphore
Right port writes 0 to semaphore
Right port writes 1 to semaphore
Left port writes 0 to semaphore
Left port writes 1 to semaphore
I/O
0
–I/O
17
Left I/O
0
–I/O
17
Right
1
0
0
1
1
0
1
1
1
0
1
1
1
1
0
0
1
1
0
1
1
1
Semaphore-free
Left Port has semaphore token
No change. Right side has no write access to semaphore
Right port obtains semaphore token
No change. Left port has no write access to semaphore
Left port obtains semaphore token
Semaphore-free
Right port has semaphore token
Semaphore free
Left port has semaphore token
Semaphore-free
Status
Notes:
9. See Functional Description for specific highest memory locations by device.
10. If BUSY
R
=L, then no change.
11. If BUSY
L
=L, then no change.
12. See Functional Description for specific addresses by device.
Document #: 38-06052 Rev. *H
Page 7 of 19
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