61 lines
1.4 KiB
C++
61 lines
1.4 KiB
C++
/*
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* EEPROM Write
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*
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* Stores values read from analog input 0 into the EEPROM.
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* These values will stay in the EEPROM when the board is
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* turned off and may be retrieved later by another sketch.
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*/
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#include <EEPROM.h>
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/** the current address in the EEPROM (i.e. which byte we're going to write to next) **/
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int addr = 0;
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void setup() {
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/** Empty setup. **/
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}
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void loop() {
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/***
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Need to divide by 4 because analog inputs range from
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0 to 1023 and each byte of the EEPROM can only hold a
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value from 0 to 255.
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***/
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int val = analogRead(0) / 4;
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/***
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Write the value to the appropriate byte of the EEPROM.
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these values will remain there when the board is
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turned off.
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***/
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EEPROM.write(addr, val);
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/***
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Advance to the next address, when at the end restart at the beginning.
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Larger AVR processors have larger EEPROM sizes, E.g:
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- Arduno Duemilanove: 512b EEPROM storage.
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- Arduino Uno: 1kb EEPROM storage.
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- Arduino Mega: 4kb EEPROM storage.
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Rather than hard-coding the length, you should use the pre-provided length function.
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This will make your code portable to all AVR processors.
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***/
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addr = addr + 1;
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if (addr == EEPROM.length()) {
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addr = 0;
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}
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/***
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As the EEPROM sizes are powers of two, wrapping (preventing overflow) of an
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EEPROM address is also doable by a bitwise and of the length - 1.
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++addr &= EEPROM.length() - 1;
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***/
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delay(100);
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}
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