[minima] Re: si570 Output Enable Polarity?
- From: "Mac A. Cody" <maccody@xxxxxxx>
- To: minima@xxxxxxxxxxxxx
- Date: Wed, 05 Mar 2014 23:11:32 -0600
Mike,
That brings up an interesting question. I took a look again
atthe Digi Board PCB that was developed by Adrian YO4HHP. It
turns out that the enable pad is neither connected to ground
(logic 'low') nor 3.3 V (logic 'high'). It is simply allowed
to float. Given that most of the CMOS Si570s being sold are
Si570CAC, the output enable is logic 'high'. This enables a
fortunate situation given that open CMOS inputs tend to float
to logic 'high'. Still, I see this as possibly an oversight
on the design of Digi Board PCB. Of course, I could be wrong
and Adrian left it up to the used to strap the output enable
pad as desired.
My short answer is to obtain an Si570CAC, as that is probably
what will be sold to you anyway. Just make sure that there
is an appropriate pull-up for the output enable pad.
73,
Mac AE5PH
On 03/05/2014 09:00 AM, hcker2000 wrote:
Do I need a chip with high or low output enable polarity?
--
Mike "hcker2000" Ashcraft
http://bigironinteractive.com
<http://www.linkedin.com/in/mikeashcraft>
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