AN2014 datasheet(56/65 Pages) STMICROELECTRONICS

Teilenummer	AN2014

Bauteilbeschribung	How a designer can make the most of STMicroelectronics serial EEPROMs

PDF	65 Pages

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Hersteller	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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56 / 65 page

Power supply loss and application reset

AN2014

56/65

DocID10701 Rev 10

Figure 45. Emergency sequence SPI products

Note:

If the emergency software sequence can be executed so that the EEPROM is not

deselected at a data byte boundary (multiple of 8 bits), there is no risk of triggering a write

cycle.

After the emergency sequence, the power supply of the EEPROM (through keep alive

systems or a backup capacitor at the EEPROM level) must remain high enough to allow an

eventual write cycle to complete correctly.

MICROWIRE products

Emergency procedure to interrupt a MICROWIRE request:

•

drive W pin low for M93Sxx(c) devices. One clock pulse will discard the current write

request.

•

deselect the EEPROM by driving the S pin Low.

Warning:

If the chip is deselected between two data bytes of a write

request and W has not been driven Low, a write cycle may be

triggered (see Figure 46: Emergency sequence MICROWIRE

products)

c. W pin is available on M93Sxx products (not available on M93Cxx products).

AN2014 Datenblatt(PDF) 56 Page - STMicroelectronics