CY7C024_09 Datasheet, PDF (6/21 Pages) Cypress Semiconductor – 4K x 16/18 and 8K x 16/18 Dual-Port Static RAM with SEM, INT, BUSY

CY7C024/024A/0241
CY7C025/0251
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/O₀–I/O_15/17
Left
1
0
0
1
1
0
1
1
1
0
1
I/O₀–I/O_15/17
Right
1
1
1
0
0
1
1
0
1
1
1
Status
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
Notes
7. A_0L–12L and A_0R–12R, 1FFF/1FFE for the CY7C025.
8. If BUSY_R=L, then no change.
9. If BUSY_L=L, then no change.
Document #: 38-06035 Rev. *D
Page 6 of 21
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