Hi ...<br>I haven't used that chip, but on most you have to make sure you enable the interrupt on the RTC and make sure you have the correct alarm rate plugged into the registers. Does the RTC actually keep time (is it actually running)? I had one chip where I had to short the external back-up battery pin to ground momentaraliy before things would run. You must also clear the alarm interrupt on the RTC before another will occur too.
<br><br>that's my 2 cents....<br><br><br><div><span class="gmail_quote">On 10/2/07, <b class="gmail_sendername">John Baraclough</b> <<a href="mailto:j_baraclough@zetnet.co.uk">j_baraclough@zetnet.co.uk</a>> wrote:
</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hi Andy,<br><br>First hang an LED on the 1Hz output to make sure the oscillator is<br>
running correctly. Then put an external 10k pull-up on PE4, just in<br>case the internal pull-ups aren't working for some reason.<br><br>All the best for now,<br>John<br><br>At 17:35 02/10/2007, you wrote:<br>>Hi<br>
><br>>We're having trouble with the alarm on a MAX6917 I2C uP Supervisor/RTC<br>>device.<br>><br>>I2C comms to the device is working fine and we can read/write all RTC<br>>registers. The ALM output of the MAX6917 is connected directly to the INT4
<br>>(PE4) input of a Mega2560 with internal pullup enabled.<br>><br>>We just can't get this beast to generate an interrupt, either at a specific<br>>time, or even once per second.<br>><br>>We've tried this on three different boards and my h/w guy (who's just shoved
<br>>off on holiday) assures me that the design is good and that the boards are<br>>not faulty.<br>><br>>Any gotchas I'm missing ? Or other suggestions ?<br>><br>>TIA.<br>><br>>Andy.<br>><br>
>--<br>> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><br>> >><br>> >> Andy Syms Technosoft Systems Ltd
<br>> >><br>> >> email : <a href="mailto:asyms@technosoft.co.uk">asyms@technosoft.co.uk</a><br>> >> website : <a href="http://www.technosoft.co.uk">www.technosoft.co.uk</a><br>> >>
<br>> >> tel : +44 (0) 1483 799554<br>> >> fax : +44 (0) 1483 799664<br>> >><br>> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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