X88257 Datasheet, PDF (5/15 Pages) Xicor Inc. – E2 Micro-Peripheral

X88257
TOGGLE BIT POLLING
Because the typical write timing is less than the specified
5ms, Toggle Bit Polling has been provided to determine
the early end of write. During the internal programming
cycle I/O₆ will toggle from “1” to “0” and “0” to “1” on
Toggle Bit Polling RD/WR Control
subsequent attempts to read the device. When the
internal cycle is complete the toggling will cease and the
device will be accessible for additional read or write
operations.
OPERATION
LAST BYTE
WRITTEN
CE
I/O6=X
I/O6=X
I/O6=X
I/O6=X
X88C64 READY FOR
NEXT OPERATION
ALE
A/D0–A/D7
AIN DIN
AIN DOUT
AIN DOUT
AIN DOUT
AIN DOUT
AIN
A8–A14
An
An
An
An
An
ADDR
WR
RD
SOFTWARE DATA PROTECTION
Software Data Protection (SDP) is employed to protect
the entire array against inadvertent writes. To write to the
X88257, a three-byte command sequence must precede
the byte(s) being written. All write operations, both the
command sequence and any data write operations must
conform to the page write timing requirements.
Writing with SDP
WRITE AA
TO 5555
WRITE 55
TO 2AAA
6509 ILL F09.1
WRITE A0
TO 5555
PERFORM BYTE
OR PAGE WRITE
OPERATIONS
WAIT tWC
EXIT ROUTINE
6509 ILL F10.1
5