7 Feb
2015
7 Feb
'15
3:56 p.m.
On 2015-Feb-07, at 8:47 AM, Noel Chiappa wrote:
You shouldn't need to do anything regarding pin 1, (this) datasheet indicates they
(the FOX F5C-2 series) have an internal pull-up R on pin 1,
so the output should be active by default.
http://www.datasheets360.com/pdf/8636385546948709069
As your fault description sounds like it could be stuck in tri-state, you could try an
experiment with your existing osc. and pull pin 1 high through an R to see if it
activates, on the small probability the internal fault is loss of that internal R.
I have one 13.824 unit I was going to offer but Tothwolf has lots of them, so all the
better there.
They are a baud-rate generator frequency for the standard (300..9600..19200...) baud rate
series as well as the 14400..57600.. series.
Could probably be found in some 90s-era modems.
If you want to be comprehensive/paranoid you could still affirm that inverter input is
functioning properly on the also-small probability a fault there wrecked the oscillator
output.
From: Tothwolf
Before I forget again, did you check for +5V on
pin 1 (enable) when you
were testing your existing oscillator?
Wow. Never thought to try that. Then again, I don't look for +5V on your
average 74xxx when I'm debugging, either! :-) I mean, it's a trace, the
solder on the pin looks good, that's as far as I go, usually! And there's
nothing shown as connected to that pin on the circuit diagram.
So I looked, and... it's at ground (or floating). The only pin that has
anything is 14, at +5V (expected). But I looked online for some datasheets
for similar oscillators, and some of them say 'pin 1 - N/C'. Are yours
tri-state? (That's the enable pin on the tri-state ones.)
I suppose even if yours are tri-state, I can still use them; a quick ohmmeter
check shows that pin 1 isn't connected to either power or ground, so I can
probably tie it high (via a resistor, which in addition to being normal
practise, will prevent a major disaster in case I'm confused - a state I'm
often in :-).