CY14E256LA-ZS25XI CYPRESS [Cypress Semiconductor], CY14E256LA-ZS25XI Datasheet - Page 7

• Manufacturer Part Number: CY14E256LA-ZS25XI
• Description: 256 Kbit (32K x 8) nvSRAM
• Manufacturer: CYPRESS [Cypress Semiconductor]

Best Practices
nvSRAM products have been used effectively for over 15 years.
While ease-of-use is one of the product’s main system values,
experience gained working with hundreds of applications has
resulted in the following suggestions as best practices:
■
Document Number: 001-54952 Rev. *B
The nonvolatile cells in this nvSRAM product are delivered from
Cypress with 0x00 written in all cells. Incoming inspection
routines at customer or contract manufacturer’s sites
sometimes reprogram these values. Final NV patterns are
typically repeating patterns of AA, 55, 00, FF, A5, or 5A. End
product’s firmware should not assume an NV array is in a set
programmed state. Routines that check memory content
values to determine first time system configuration, cold or
warm boot status, and so on should always program a unique
NV pattern (that is, complex 4-byte pattern of 46 E6 49 53 hex
or more random bytes) as part of the final system manufac-
turing test to ensure these system routines work consistently.
■
■
Power up boot firmware routines should rewrite the nvSRAM
into the desired state (for example, autostore enabled). While
the nvSRAM is shipped in a preset state, best practice is to
again rewrite the nvSRAM into the desired state as a safeguard
against events that might flip the bit inadvertently such as
program bugs and incoming inspection routines.
The V
and a maximum value size. Best practice is to meet this
requirement and not exceed the maximum V
the nvSRAM internal algorithm calculates V
discharge time based on this maximum V
that want to use a larger V
store charge and store time should discuss their V
selection with Cypress to understand any impact on the V
voltage level at the end of a t
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value specified in this data sheet includes a minimum
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value to make sure there is extra
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period.
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value. Customers
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size
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