STR750 RTC clock input

[jpeacock2]

Posted on April 25, 2007 at 05:54

STR750 RTC clock input

[jpeacock2]

Posted on April 23, 2007 at 17:09

Can the 32.768Khz RTC clock on the STR750 be driven by an external Oscillator instead of a crystal or resonator? I would like to use the 32Khz output from an ST M41ST87W RTC/tamper chip to drive the STR750 RTC clock.

[mohamed23]

Posted on April 23, 2007 at 20:56

Hi JakBird,

I think that you can do that. Have a quick look on datasheet for connections. Regards, Rave

[jpeacock2]

Posted on April 24, 2007 at 16:30

The datasheet only shows crystal or resonator for the RTC clock pins. The Hardware Getting Started guide also implies only a crystal or resonator. I didn't find any place that explicitly states an external oscillator can or can't be used on the RTC pins.

[jgoril]

Posted on April 25, 2007 at 05:54

See datasheet, rev. 3, at page 44/71, chapter XRTC1 external clock source... It says that external clock source with frequency of 500kHz max. can be connected to pin XRTC1, while XRTC2 is Hi-Z 🙂