eeprom¶

Stores values read from analog input 0 into the EEPROM. These values will stay in the EEPROM when the board is turned off and may be retrieved later by another sketch.

Sketch¶

The sketch can be found here.

Hypothesis¶

A variable value is lost when the Feather goes into a deep sleep but can be stored and retrieved in the EEPROM.

Assumptions¶

WIP

Procedure¶

Circuit¶

Same circuit as battery.

Circuit made with Circuit Diagram

Code¶

The Feather takes a reading of the A0 pin, divides the value by 4, prints the value, then saves it to the EEPROM.

The Feather then goes into a deep sleep for a period of time.

On next bootup, the same variable is printed to the console and the EEPROM saved values are retrieved and printed to the console.

Output¶

The Retrieved pin value of the current reading should match the Write pin value of the previous reading.

The Retrieved didNotify of the current reading should match the Write didNotify of the previous reading.

The Variable value should be 0 when the Feather wakes up again because the variable is not retained.

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eeprom
Retrieved pin value: 239
Variable value: 0
Retrieved didNotify: 1
Write pin value: 240
Write didNotify: 0
EEPROM successfully committed
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eeprom
Retrieved pin value: 240
Variable value: 0
Retrieved didNotify: 0
Write pin value: 240
Write didNotify: 1
EEPROM successfully committed
...

Analysis¶

Everything worked as expected.

The original variable was reset to 0 after waking up from a deep sleep.

The value was able to be successfully stored and retrieved in the EEPROM before and after the deep sleep respectively.

Conclusion¶

If a sketch uses the deep sleep mode and a previous values is to be used again, it firsts needs to be saved to the EEPROM and then retrieved on the next boot.

Troubleshooting¶

WIP