> -----Original Message-----
> From: =D6mer Yalhi [SMTP:oyalhi@TEKSAN.COM.TR]
> Sent: Wednesday, January 15, 2003 11:18 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Saving contents of a mcu to eeprom
>=20
> Is there a way to save couple of bytes (8 or 10 bytes) to eeprom just
> before power outage?
>=20
> * I am using MPLAB C18 (the software is in C)
> * The unit is working with 220V AC converted to 12V DC then 5V DC.
> * Configuration bit is set so power on reset on, brown out detection on,
> brown out voltage 4.2, oscillator H4 (10MHz xtal working at 40MHz).
>=20
> I looked up the datasheet, according to page 27, I checked the RCON
> registers POR bit (that is the only one affected with brown out for some
> reason) and saved 8 bytes to eeprom if the POR bit was 1.  I did this at
> the very first thing in the main() procedure.  However, it did not work.
> Any ideas?
>=20
> If anyone is interested the product can be seen at:
> http://www.teksan.com.tr/vana.asp?L=3DE&Id=3D0401
> or goto http://www.teksan.com.tr, select product then bathcing solutions.
>=20
> Thanks,
>=20
> =D6mer YALHI
>=20
Check out the Low Voltage Detect (LVD) function.  This is effectively a
comparator with an adjustable reference set using the LVDCON register.  If
the supply falls below the reference voltage, and interrupt will be
generated which you can capture and use to store you data.

Ensure you have enough time remaing to store your 10bytes after the
interrupt, the EEPROM memory typicaly takes 4ms per byte to write.

Regards

Mike


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