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MODE
PIN FUNCTION
READ OR OUTPUT DISABLE
A2
CP/PGM
(OE/OES)/VFY
INIT/VPP
A1
OUTPUTS
Read (Note 6)
X
VIL
VIH
X
Data Out
Output Disable
X
VIH
X
High Z
Program (Notes 5 & 7)
X
VIL
VIH
VPP
X
Data In
Program Verify (Notes 5 & 7)
X
VIH
VIL
VPP
X
Data Out
Program Inhibit (Notes 5 & 7)
X
VIH
VPP
X
High Z
Intelligent Program (Notes 5 & 7)
X
VIL
VIH
VPP
X
Data In
Program Synch Enable (Note 7)
VIH
VIL
VIH
VPP
High Z
Program Initial Byte (Note 7)
VIL
VIH
VPP
Data In
Initial Byte Read
X
VIL
X
Data Out
WS57C45
2-26
NOTES: 5. X = Don’t Care but not to exceed VPP.
6. During read operation, the output latches are loaded on a “0” to “1” transition of CP.
7. During programming and verification, all unspecified pins to be at VIL.
Synchronous Enable Programming
The WS57C45 contains both a synchronous and asynchronous enable feature. The part is delivered configured in
the asynchronous mode and only requires alteration if the synchronous mode is required. This is accomplished by
programming an on-chip EPROM cell. Similar to the Initial Byte, this function is enabled and addressed by using a
super voltage. Referring to the Mode Selection table, VPP is applied to A1 followed by VIH applied to A2. This
procedure addresses the EPROM cell that programs the synchronous enable feature. The EPROM cell is
programmed with a 10 ms program pulse on CP/PGM. It does not require any data since there is no selection as to
how synchronous enable may be programmed, only if it is to be programmed.
Synchronous Enable Verification
The WS57C45’s synchronous enable function is verified operationally. Apply power for read operation with OE/OES
and INIT/VPP at VIH and take the clock (CP/PGM) from VIL to VIH. The output data bus should be in a high
impedance state. Next take OE/OES to VIL. The outputs will remain in the high impedance state. Take the clock
(CP/PGM) from VIL to VIH and the outputs will now contain the data that is present. Take OE/OES to VIH. The output
should remain driven. Clocking CP/PGM once more from VIL to VIH should place the outputs again in a high
impedance state.
Blank Check
Upon delivery from WaferScale Integration, Inc. or after each erasure (see Erasure section), the WS57C45 has all
2048 bytes in the ‘0’ state. “1’s” are loaded into the WS57C45 through the procedure of programming.