CY7C027V/028V
CY7C037V/038V
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)
[42]
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–14L
7FFF
X
X
7FFE
INT
L
X
X
L
[43]
H
[44]
R/W
R
X
X
L
X
CE
R
X
L
L
X
Right Port
OE
R
X
L
X
X
A
0R–14R
X
7FFF
7FFE
X
INT
R
L
[44]
H
[43]
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:
42. A
0L–15L
and A
0R–15R
,FFFF/FFFE for the CY7C028V/038V.
43. If BUSY
R
=L, then no change.
44. If BUSY
L
=L, then no change.
Document #: 38-06078 Rev. *A
Page 15 of 18
CYPRESS [ CYPRESS SEMICONDUCTOR ]
