at90s2323 ATMEL Corporation, at90s2323 Datasheet - Page 34

• Manufacturer Part Number: at90s2323
• Description: 8-bit Microcontroller With 2k Bytes Of In-system Programmable Flash At90s2323 At90ls2323 At90s2343 At90ls2343
• Manufacturer: ATMEL Corporation

Prevent EEPROM
Corruption
34
AT90S/LS2323/2343
During periods of low V
age is too low for the CPU and the EEPROM to operate properly. These issues are the
same as for board level systems using the EEPROM and the same design solutions
should be applied.
An EEPROM data corruption can be caused by two situations when the voltage is too
low. First, a regular write sequence to the EEPROM requires a minimum voltage to
operate correctly. Secondly, the CPU itself can execute instructions incorrectly, if the
supply voltage for executing instructions is too low.
EEPROM data corruption can easily be avoided by following these design recommen-
dations (one is sufficient):
1. Keep the AVR RESET active (low) during periods of insufficient power supply
2. Keep the AVR core in Power-down Sleep mode during periods of low V
3. Store constants in Flash memory if the ability to change memory contents from
voltage. This is best done by an external low V
referred to as a Brown-out Detector (BOD). Please refer to application note AVR
180 for design considerations regarding power-on reset and low-voltage
detection.
will prevent the CPU from attempting to decode and execute instructions, effec-
tively protecting the EEPROM registers from unintentional writes.
software is not required. Flash memory cannot be updated by the CPU and will
not be subject to corruption.
CC
, the EEPROM data can be corrupted because the supply volt-
CC
Reset Protection circuit, often
CC
. This
1004D–09/01