CY7C027V/028V
CY7C037V/038V
Table 1. Non-Contending Read/Write
Inputs
Outputs
CE
H
X
L
R/W
X
OE
X
X
X
X
X
L
UB
X
H
L
LB
X
H
H
L
SEM
H
H
H
H
H
H
H
H
X
I/O9–I/O17
High Z
I/O0–I/O8
High Z
Operation
Deselected: Power-Down
Deselected: Power-Down
Write to Upper Byte Only
Write to Lower Byte Only
Write to Both Bytes
X
High Z
High Z
L
Data In
High Z
High Z
L
L
H
L
Data In
Data In
High Z
L
L
L
Data In
Data Out
High Z
L
H
H
H
X
L
H
L
Read Upper Byte Only
Read Lower Byte Only
Read Both Bytes
L
L
H
L
Data Out
Data Out
High Z
L
L
L
Data Out
High Z
X
H
X
H
H
L
X
X
H
X
X
X
H
X
Outputs Disabled
H
H
L
Data Out
Data Out
Data In
Data Out
Data Out
Data In
Read Data in Semaphore Flag
Read Data in Semaphore Flag
Write DIN0 into Semaphore Flag
L
L
X
L
X
X
H
H
L
Data In
Data In
Write DIN0 into Semaphore Flag
L
L
X
X
X
X
L
X
L
L
L
Not Allowed
Not Allowed
X
Table 2. Interrupt Operation Example (assumes BUSYL=BUSYR=HIGH)[42]
Left Port
Right Port
Function
R/WL CEL
OEL
X
A0L–14L
7FFF
X
INTL R/WR CER
OER
X
A0R–14R
X
INTR
L[44]
H[43]
X
Set Right INTR Flag
Reset Right INTR Flag
Set Left INTL Flag
Reset Left INTL Flag
L
X
X
X
L
X
X
L
X
X
X
L
X
L
L
X
X
X
L
7FFF
7FFE
X
X
X
L[43]
H[44]
X
L
7FFE
X
X
X
Table 3. Semaphore Operation Example
Function I/O0–I/O17 Left I/O0–I/O17 Right
Status
No action
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
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
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
Left port writes 1 to semaphore
Notes:
42.
A
and A
,FFFF/FFFE for the CY7C028V/038V.
0L–15L
0R–15R
43. If BUSY =L, then no change.
R
44. If BUSY =L, then no change.
L
Document #: 38-06078 Rev. *A
Page 15 of 18
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