DS3232 Question

[zener]

Hi All,

I would just like to get confirmation on what I am doing is correct before going any further.

Attached is a typical circuit for the DS3232 RTC and my circuit for the 28x2.

My question is:
Am I correct if I connect the reset from the DS3232 to the 28x2 that has a pullup resistor and a reset button and eliminating the reset button that is shown on the DS3232 typical circuit diagram?

Thanks

 

[Hemi345]

The DS3232 datasheet (page 9) says you shouldn't connect an external pullup resistor on the reset line since it has an internal 50k pullup. But I don't know if that 50k would be enough to keep the 28x2 out of reset.

 

[inglewoodpete]

Try it. The reset pin on the PICAXE will have a pretty high impedance. If the 50k pullup within the DS3232 is not adequate to keep the PICAXE running, then add a 4.7k pullup with an isolating diode back to the reset switch.

 

[zener]

Thanks to Hemi345 & inglewoodpete for your input.

Other questions I should have asked is:

Do I need to connect the DS3232 to the picaxe?

Am I better off connecting the DS3232 to another pin on the picaxe?

How have other users of this chip connected it to their picaxe?

Thanks again

 

[MartinM57]

/RST not connected I.e. using internal pull up to keep a logic high

Why do you need to reset the DS3232? You can do everything you want to it via its commands

 

[zener]

Why do you need to reset the DS3232? You can do everything you want to it via its commands

I thought that because the "Typical circuit" indicates that it connects to the micro-controller pin that I should as well.
Having not used this RTC before I am not sure why I would have to reset it.

I'm hoping to learn what other users typically do with the reset pin of the DS3232.

Thanks

 

[marks]

Hi zener,
heres another example you may be interested in
the ds3232 is identical to the ds3231 tho doesnt have the usuable memory but uses half the power,
you should be able to use the same code and circuit .
http://www.picaxeforum.co.uk/showthread.php?19537-LCD-1602-driven-by-PICAXE-20x2-and-DS3231SN
http://www.picaxeforum.co.uk/showthread.php?18694-DS3231-Code-examples

 

[Hemi345]

I've used the DS3232 in quite a few projects but with the PICAXE that don't have a reset (14M2, 20X2). I just left the reset line unconnected.

The DS3232's SRAM's unlimited writes is handy for saving memory values for program recovery after power failure.

 

[zener]

Thank you all who responded.

I think I will add a reset button and not connect it to anything else.

Thanks