CY7C024/024A/0241
CY7C025/0251
Document #: 38-06035 Rev. *D
Page 6 of 21
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
7. A0L–12L and A0R–12R, 1FFF/1FFE for the CY7C025.
8. If BUSYR=L, then no change.
9. If BUSYL=L, then no change.
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