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Emergency power-off MC55i | Telit Cinterion IoT Developer Community

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arossi's picture
arossi

June 19, 2019 - 12:04pm, 1331 views

Hello,

I would like to understand better why the emergency power-off is "dangerous" on MC55i. In the datasheet I read:

"Caution: Use the EMERGOFF pin only when, due to serious problems, the software is not responding for more than 5 seconds. Pulling the EMERGOFF pin causes the loss of all information stored in the volatile memory since power is cut off immediately. Therefore, this procedure is intended only for use in case of emergency, e.g. if MC55i fails to shut down properly."

What does really happen to the module? Is the module writing on its flash and when the power supply is cut off, the flash can be corrupted? Or something else?

Thanks.

Best regards.

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Bartłomiej Gemalto Moderator's picture
Bartłomiej Gema...
Jun 19 2019 - 4:39pm

Hello,

It is a general advise for all modules to be switched off by software (AT commnad) as then the system can finalize all the critical operations, deregister from the network and so on. EMERGOFF should be used as a last instance, for example in case there is no contact with the module for any reason and it is not possible to execute AT command.

You are right that it is possible, the probability is very low but anyway there is some chance that when the power is cut off during a flash write cycle the module can be damaged because some data may be corrupted.

Best regards,

Bartłomiej