Cypress CY7C145 Manual De Usuario
CY7C145, CY7C144
Document #: 38-06034 Rev. *D
Page 15 of 21
Table 3. Non-Contending Read/Write
Inputs
Outputs
CE
R/W
OE
SEM
I/O
0
−7/8
Operation
H
X
X
H
High Z
Power-Down
H
H
L
L
Data Out
Read Data in Semaphore
X
X
H
X
High Z
I/O Lines Disabled
H
X
L
Data In
Write to Semaphore
L
H
L
H
Data Out
Read
L
L
X
H
Data In
Write
L
X
X
L
Illegal Condition
Table 4. Interrupt Operation Example (assumes BUSY
L
= BUSY
R
= HIGH)
Function
Left Port
Right Port
R/W
CE
OE
A
0
−12
INT
R/W
CE
OE
A
0
−12
INT
Set Left INT
X
X
X
X
L
L
L
X
1FFE
X
Reset Left INT
X
L
L
1FFE
H
X
L
L
X
X
Set Right INT
L
L
X
1FFF
X
X
X
X
X
L
Reset Right INT
X
X
X
X
X
X
L
L
1FFF
H
Table 5. Semaphore Operation Example
Function
I/O
0-7/8
Left
I/O
0-7/8
Right
Status
No action
1
1
Semaphore free
Left port writes semaphore
0
1
Left port obtains semaphore
Right port writes 0 to semaphore
0
1
Right side is denied access
Left port writes 1 to semaphore
1
0
Right port is granted access to semaphore
Left port writes 0 to semaphore
1
0
No change. Left port is denied access
Right port writes 1 to semaphore
0
1
Left port obtains semaphore
Left port writes 1 to semaphore
1
1
No port accessing semaphore address
Right port writes 0 to semaphore
1
0
Right port obtains semaphore
Right port writes 1 to semaphore
1
1
No port accessing semaphore
Left port writes 0 to semaphore
0
1
Left port obtains semaphore
Left port writes 1 to semaphore
1
1
No port accessing semaphore