Subject: Xtal/chip combo for 60 Hz ?
From:
[email protected]
Date: 5/14/2004 3:20 PM Central Standard Time
Message-id:
<c2Fnb2JvZw==.0c71848ceec5f0e37649ed5324dfb857@1084566036.nulluser.com>
Is there a commonly available crystal and divider chip combination to
generate 60 Hz?
Of course, the customary solution for this is to use the 60 Hz line frequency
to do this. Otherwise, the customary answer is to generate an interrupt off of
your microcontroller timer/counter using the crystal-based uC clock frequency.
But somehow, I don't think that's what you're looking for.
Given that, I don't think there's a one-chip solution that will get you where
you want to go. An older UART crystal frequency of 1.2288 MHz will get you a
two-chip solution (view in fixed font or M$ Notepad):
60 Hz From Crystal or Oscillator
.-----------------.
| | .--------------.
..-----o-----. | | | |
| | | CLK /2^11| | |
| 1.2288MHz o----o CD4040 o------oCLK |
| | | | | CD4017 |
| | | | | |
'-----o-----' | | .-oEN |
| | | | |
| | | | OUT/10 |
| | | '-------o------'
'-----------------' | |
=== |
GND |
|
|
o
60 Hz
Squarewave
A cursory scan doesn't show any crystals at this frequency from the usual
hobbyist suspects, but you can get a full-size TTL/CMOS-compatible clock
oscillator at this frequency from Mouser for $1.50 USD from Mouser (P/N
520-TCF122). Have fun.
Good luck
Chris
