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switching out a DS1302 with a DS1307 BATT charger question — Parallax Forums

switching out a DS1302 with a DS1307 BATT charger question

KC8DKTKC8DKT Posts: 76
edited 2006-02-25 02:39 in BASIC Stamp
·I replaced my·DS1302 with a·DS1307.···Got everything working but there is no charge current when the VCC is restored to charge the batt.·· The data sheet does say "UL recognized to ensure against reverse charging current when used with a lithium battery".·· Is there a way to turn this On/Off like with the DS1302 that I am missing or what?· There is no setting for this on the data sheet or listed anywhere I can find.

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-02-24 23:56
    The DS3017 is designed for a lithium battery and does no charging.· I think that note means that the DS1307 is protected against a battery that is installed backwards.

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    Jon Williams
    Applications Engineer, Parallax
  • KC8DKTKC8DKT Posts: 76
    edited 2006-02-25 00:14
    Is there a way to connect a 5.5v SupperCap to the VDD to charge with a diod/resistor and to the 1307 Bat Backup pin? I know I need a resistor to bring the 5.5v down to 3v for the 1307 unlike the 1302.
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-02-25 02:39
    Since the DS1307 is designed for a lithium backup, you might want to stick with that (no bigger than the supercap, and easier to deal with). If you can't use the battery for some reason then you might want to check the Maxim/Dallas site for a possible app note.

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    Jon Williams
    Applications Engineer, Parallax
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