93AA46A_07 Datasheet, PDF (13/38 Pages) Microchip Technology – 1K-16K Microwire Compatible Serial EEPROMs

93XX46X/56X/66X/76X/86X
3.6 ERASE/WRITE DISABLE And
ENABLE (EWDS/EWEN)
The 93XX series devices power-up in the Erase/Write
Disable (EWDS) state. All programming modes must
be preceded by an Erase/Write Enable (EWEN) instruc-
tion. Once the EWEN instruction is executed, program-
ming remains enabled until an EWDS instruction is
executed or VCC is removed from the device.
To protect against accidental data disturbance, the
EWDS instruction can be used to disable all Erase/Write
functions and should follow all programming
operations. Execution of a READ instruction is
independent of both the EWEN and EWDS instructions.
FIGURE 3-5:
EWDS TIMING
CS
TCSL
CLK
DI
1
00
00
x
•••
x
FIGURE 3-6:
EWEN TIMING
TCSL
CS
CLK
DI
1
00
1
1x
•••
x
© 2007 Microchip Technology Inc.
DS21929D-page 13