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update()
Description
Write a byte to the EEPROM. The value is written only if differs from the one already saved at the same address.
Syntax
EEPROM.update(address, value)
Parameters
address: the location to write to, starting from 0 (int)
value: the value to write, from 0 to 255 (byte)
Returns
none
Note
An EEPROM write takes 3.3 ms to complete. The EEPROM memory has a specified life of 100,000 write/erase cycles, so using this function instead of write() can save cycles if the written data does not change often
Example
#include <EEPROM.h>
void setup()
{
for (int i = 0; i < 255; i++) {
// this performs as EEPROM.write(i, i)
EEPROM.update(i, i);
}
for (int i = 0; i < 255; i++) {
// write value "12" to cell 3 only the first time
// will not write the cell the remaining 254 times
EEPROM.update(3, 12);
}
}
void loop()
{
}
See also
- EEPROM.write()
- EEPROM.read()
- EEPROM.put()
- EEPROM.get()
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The text of the Arduino reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.
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