atmega103 ATMEL Corporation, atmega103 Datasheet - Page 59

• Manufacturer Part Number: atmega103
• Description: Atmega103 8-bit With 128k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

Prevent EEPROM
Corruption
0945I–AVR–02/07
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. Second, the CPU itself can execute instructions incorrectly if the sup-
ply 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
ATmega103(L)
CC
. This
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