freqout command
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Posts: 46,084
Can someone please explain the freqout command? Can I use a simple divide by
n IC to divide down the output generated by freqout? Can I use a simple PLL
frequency multiplier to multiply up the output generated by freqout? Thanks!
n IC to divide down the output generated by freqout? Can I use a simple PLL
frequency multiplier to multiply up the output generated by freqout? Thanks!
Comments
tries to make quasi sine waves and I don't think you would have much
luck with this. If you want to make nice pulse trains out, have a look
at the PAK-VIII: http://www.al-williams.com/awce/pak8.htm. An even
better question is: what do you want to do (not how do you want to do
it).
Al Williams
AWC
* Easy RS-232 Prototyping
http://www.al-williams.com/awce/rs1.htm
>
Original Message
> From: azeasi@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=MbooDDg7msIlhHoex6KruYDULHJQei7JxLeMrl0QktDicSo4PvH-SXfOsdt8D2zx97tM-fWTlXY]azeasi@a...[/url
> Sent: Monday, February 11, 2002 11:32 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] freqout command
>
>
> Can someone please explain the freqout command? Can I use a
> simple divide by
> n IC to divide down the output generated by freqout? Can I
> use a simple PLL
> frequency multiplier to multiply up the output generated by
> freqout? Thanks!
>
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better resolution (1 Hz increments from 1 to 100,000 Hz). I am using the PAK8
with a 1:1 prescale which produces 5 us pulse width. This is OK for the 100
kHz that I need. But I can't get anything between 50,000 and 100,000 Hz with
this. I need four channels all running at the same time with this range of
output signals. If I could get 0.5 us pulse widths out of the PAK I would be
closer to what I need. I thought of using the pulse out command and the pause
command but the pause command only works in multiples of 1 ms. I only need
two different frequencies at the same time but I need to change these to two
other frequencies every second and so forth. Any suggestions? I I have to, I
can live with a smaller range like (10 Hz to 65,500 Hz). The reason I asked
about the divide by 10 circuit is that I also need to be able to program in
frequencies with 0.1 Hz resolution. If for instance I need 101.1 Hz, I would
program 1011 Hz and divide by 10. I thought of using a PLL but I need a
100,000 to 1 range for the VCO! Any help would be appreciated.
This uses the intriguing new LT1799 programmable oscillator from
Linear tech, along with a digital potentiometer. It probably doesn't
have the accuracy you need, but it's worth bookmarking.
The HSP45102 from Harris/Intersil <http://www.intersil.com>is a chip
for direct digital synthesis of frequencies (12-bit sine waves) up to
40 mhz, with 32 bit resolution. (That is 0.009 Hertz per step!)
The control is by serial SPI, so it is well suited to Stamp control.
Each chip has two frequency control registers and can switch between
them in less than one cycle for rapid frequency hopping.
-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com
>Thanks for responding. I am actually using the PAK8 now but need to get
>better resolution (1 Hz increments from 1 to 100,000 Hz). I am using the PAK8
>with a 1:1 prescale which produces 5 us pulse width. This is OK for the 100
>kHz that I need. But I can't get anything between 50,000 and 100,000 Hz with
>this. I need four channels all running at the same time with this range of
>output signals. If I could get 0.5 us pulse widths out of the PAK I would be
>closer to what I need. I thought of using the pulse out command and the pause
>command but the pause command only works in multiples of 1 ms. I only need
>two different frequencies at the same time but I need to change these to two
>other frequencies every second and so forth. Any suggestions? I I have to, I
>can live with a smaller range like (10 Hz to 65,500 Hz). The reason I asked
>about the divide by 10 circuit is that I also need to be able to program in
>frequencies with 0.1 Hz resolution. If for instance I need 101.1 Hz, I would
>program 1011 Hz and divide by 10. I thought of using a PLL but I need a
>100,000 to 1 range for the VCO! Any help would be appreciated.
synthesis chips (numerically controlled oscillator). For example,
the N1179CM costs $23 and operates with a clock up to 25mhz. Also an
SPI interface to the CPU. If you want a square wave output instead of
sine, you can use the most significant binary output bit. (It has
jitter of at most one clock cycle).
Also, there are some DIY examples using an SX chip (with code) at:
http://www.rhoent.com/examples.htm
-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com
DigiKey has No stock. Do you know of a similar chip or someone with stock of
the Intel part?
>DigiKey has No stock. Do you know of a similar chip or someone with stock of
>the Intel part?
Ahh.. Scratch that. Try the Harris/Intersil HSP45102 instead. It
is a more capable chip, at a comparable price. It is available from
several suppliers including Newark, Allied and FAI.
-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com
did any of you run across this website with a lot of DDS info?
http://sss-mag.com/dds.html
Original Message
From: Tracy Allen [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=EM3QX8GK8Cdb9zUpUXgCgdpZm8rlX7gBSwzUmLTkxiyhyWIZLOgWTypcfJFfXIWNAWQ1EWLvosiJzg]tracy@e...[/url
Sent: Friday, February 22, 2002 10:07 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] freqout command
>Thanks! The Intel chip would be perfect except it has been obsolete and
>DigiKey has No stock. Do you know of a similar chip or someone with stock
of
>the Intel part?
Ahh.. Scratch that. Try the Harris/Intersil HSP45102 instead. It
is a more capable chip, at a comparable price. It is available from
several suppliers including Newark, Allied and FAI.
-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com
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