BeeBop

You are reading it as BCD, aren't you?

atferrari

Duly noted

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Agustín Tomás
In theory, there is no difference between theory and practice. In practice, however, there is.

ssylee

My functions processed the BCD and displayed the register contents as normal decimal numbers (integers).

Pommie

I have used breadboards for many projects and as I stated in the breadboards thread,
Aren't scope probes still around 10pF even on 10X?

Mike.

Pommie

ssylee,

Is the clock running. If so, is it running slow or fast. If you set a time and immediatly read it back, is it correct?

Mike.

ssylee

Pommie:

Should the crystal's signal be a PWM or sine waveform? B/c when I measured the clock, I don't see anything.

ssylee

I'm getting a sine wave signal between pin 3 and ground at 32.7 kHz with a peak to peak voltage of 247 mV. I don't see anything between pin 2 and ground, only a constant voltage of 200 mV. Is this an indicator of anything?

Pommie

Monitoring the crystal may stop it working. The data sheet suggests monitoring the second register in order to establish if the crystal is running. Have a read of the section "Checking For Oscillation" in the data sheet linked to earlier by Picasm.

Mike.

Blueteeth

Nothing thing aout breadboards and crystals.....of course they add all sort of parasitic stuff to it, but also, quite simply...watch crystals do not have very thick legs.....and breadboards need good pins to make contact I have had watch crystals working on a breadboard..not ideal I know but you have to solder it to a bit of stripboard then use pin headers.

My two cents.

Blueteeth

__________________
Inconsistency is the key to flexibility!

Nigel Goodwin

It's a 1/10th of what it says on the front of your scope

I regularly check oscillators on micro-controllers, at x1 it stops pretty well all of them, at x10 it usually works perfectly fine on either end of the crystal. Now I would have expected (probably like most people here?) that the lower the crystal the less effect it would have - however, like I said before, I had occasion to scope a 32KHz crystal last week, and even on x10 it killed the oscillation on one end of it.

I presume this is probably because it's a very low power circuit, so it can run off tiny batteries?.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

Pommie

Nigel,

I was questioning your statement with regard to a x10 probe, you stated, As I calculated the breadboard capacitance as 1pF and scopes are typically 15pF+ with a x10 probe, your statement appears erroneous.

Mike.

Nigel Goodwin

I was (and still am) under the impression that breadboard capacitance is considerably higher than that?.

From a Wikipedia article:

Your scope probe capacitance estimate is also much too high, from a x10 probe spec:

This would give a loading capacitance of between 1pF and 3.5pF, with 2.5pF being what the probe is designed for.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

Pommie

Maybe you can suggest where my calculation is erroneous.

A quick google finds this page which suggests that a x10 probe is 11-15pF.

Mike.

Nigel Goodwin

I wouldn't bother calculating something like that, measure it, or refer to the manufacturers measurements - for the ones which might mention it?.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

3v0

One would think that by looking a the title of a thread you could guess at about how many posts it would take to put it to rest.

There are a few things that put this out of wack.

Change of topic or hijack.
Clueless OP
The use of the word breadboard....