AN2156 Freescale Semiconductor / Motorola, AN2156 Datasheet - Page 50

• Manufacturer Part Number: AN2156
• Description: Programming and Erasing FLASH and EEPROM Memories on the MC68HC908AS60A/AZ60A
• Manufacturer: Freescale Semiconductor / Motorola

Application Note
Question 11
Answer 11
Question 12
Answer 12
FLASH Assembly Source Code Flowcharts
50
What steps can I take to prolong the life of the EEPROM memory?
The EEPROM memory has a finite program/erase durability and a finite
data retention lifetime. However, the specification quotes the minimum
guaranteed lifetime considering the worst case set of conditions applied
to the part. In general, the EEPROM array will last longer if the
program/erase cycling is kept to a minimum and the temperature is kept
at a nominal level (0–70
Can I program/erase the EEPROM at the maximum temperature limits
for the specified life of the part?
Yes. Program / erase cycle durability is specified to be 10-K minimum.
However, exceeding that value is not recommended. Reading the
EEPROM can occur continuously over the life of the product.
The main routines SSTerase.mrt and SSTprog.mrt initialize the
device for erasing and programming operations. SSTerase.mrt
specifies the size and the location of the erase block before calling the
FlashErase subroutine which follows the algorithm listed in this
application note. SSTprog.mrt fills a RAM data buffer with values to
program, specifies the location to start programming, and defines the
number of bytes of the row to program before jumping to the ProgRow
subroutine. SSTprog.mrt also includes a verification step after the
programming is completed.
The FlashErase and the ProgRow subroutines follow the flowcharts
shown in
for the WriteFLCR subroutine which is used to set or clear various bits
in the FLxCR registers and the ms_delay subroutine which generates
delays greater than 1 millisecond.
Freescale Semiconductor, Inc.
For More Information On This Product,
Figure 3
Go to: www.freescale.com
and
Figure 4
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closely. Flowcharts are also included
MOTOROLA
AN2156