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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 ( )
{
}