AUSTIN SEMICONDUCTOR, INC.
ADVANCE INFORMATION
nvSRAM
AS8nvLC512K32
Austin Semiconductor, Inc.
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:
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 nonvolatile cells in this nvSRAM product are delivered from
Austin Semiconductor 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 manufacturing test to ensure these system
routines work consistently.
The VCAP value specified in this data sheet includes a minimum
and a maximum value size. Best practice is to meet this requirement
and not exceed the maximum VCAP value because the nvSRAM
internal algorithm calculates VCAP charge and discharge time based
on this max VCAP value. Customers that want to use a larger VCAP
value to make sure there is extra store charge and store time should
discuss their VCAP size selection with Austin Semiconductor to
understand any impact on the VCAP voltage level at the end of a
tRECALL period.
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
AS8nvLC512K32
Rev. 0.0 08/09
6
AUSTIN [ AUSTIN SEMICONDUCTOR ]
