AVR-Chat

Hi,
   There are groups for AVR and ATMega which I would like to share
with all.

http://groups.yahoo.com/group/AVR_Microcontroller
http://groups.yahoo.com/group/ATMega_Microcontroller

Bye

--- In AVR-Chat@yahoogroups.com, "thefrustratedcodewarrior" 
<arif_deshmukh@r...> wrote:

> There are groups for AVR and ATMega ...

This group is all that is needed. We managed to abandon the avrclub 
group and get its members here. These other groups should be closed 
down so as not to pick up new AVR users who belong here.

Graham.

On Mon, 28 Mar 2005 18:08:20 -0000 you wrote:

>Hi,
>   There are groups for AVR and ATMega which I would like to share
>with all.
>
>http://groups.yahoo.com/group/AVR_Microcontroller
>http://groups.yahoo.com/group/ATMega_Microcontroller

Too many groups get to be a pain!
--
Ralph Hilton
http://www.ralphhilton.org
C-Meter: http://www.cmeter.org
FZAOINT http://www.fzaoint.net

At 08:02 AM 3/29/2005, Ralph Hilton wrote:

>On Mon, 28 Mar 2005 18:08:20 -0000 you wrote:
>
> >Hi,
> >   There are groups for AVR and ATMega which I would like to share
> >with all.
> >
> >http://groups.yahoo.com/group/AVR_Microcontroller
> >http://groups.yahoo.com/group/ATMega_Microcontroller
>
>Too many groups get to be a pain!

Indeed, it thins out the community.
I would hang out at "freaks" more if they would get rid of the forum 
approach, and change the name.

On Tue, 29 Mar 2005 08:13:08 -0500, Dave VanHorn <dvanhorn@dvanhorn.org>  
wrote:

>
> Indeed, it thins out the community.
> I would hang out at "freaks" more if they would get rid of the forum
> approach, and change the name.


I agree. I also prefer the mailgroup, and i see no reason to have more  
groups if there is not a clear topic difference.

ST

On Tue, 29 Mar 2005, Ralph Hilton wrote:

> On Mon, 28 Mar 2005 18:08:20 -0000 you wrote:
> 
> >Hi,
> >   There are groups for AVR and ATMega which I would like to share
> >with all.
> >
> >http://groups.yahoo.com/group/AVR_Microcontroller
> >http://groups.yahoo.com/group/ATMega_Microcontroller
> 
> Too many groups get to be a pain!
> --
> Ralph Hilton

Yes, that's for sure.  I recall when I started using AVR's I looked for 
groups on Yahoogroups and came up with half a dozen or so.  I picked a 
couple and joined them.  I eventually ended up on this group, which is the 
only one with much activity.

There is another one, AVR-DEV, set up by Diz W8DIZ of Parts and Kits 
(http://www.partsandkits.com).  He has been trying to develop a ham radio 
transceiver called the MultiPIG with an AVR controlling an AD9850 DSP 
chip.  

The last I heard from Diz, he had all but given up on the AD9850 for 
wide-frequency use because the unwanted spurs on the output were causing 
all sorts of intermod and noise floor problems and he wasn't getting the 
desired result.  

I've used the AD9850 in a very narrow-band receiver with a narrow filter 
on the output (500 kHz wide at 12 MHz) and it seemed to do a lot better, 
but if you're trying to use the 9850 as the LO for the entire shortwave 
spectrum this becomes a big problem.

So I haven't seen a posting to that group in months, either.

This is the best AVR group as far as I'm concerened.

Zack W9SZ

On Tue, 29 Mar 2005, Dave VanHorn wrote:

> At 08:02 AM 3/29/2005, Ralph Hilton wrote:
> 
> >Too many groups get to be a pain!
> 
> Indeed, it thins out the community.
> I would hang out at "freaks" more if they would get rid of the forum
> approach, and change the name.
> 

How about "AVRheads"?  (Just a joke)  :-)

Zack

Why, Why?

With this list and AVRFreaks, thats plenty!

Jim

On Mon, 28 Mar 2005 18:08:20 -0000
 "thefrustratedcodewarrior" <arif_deshmukh@rediffmail.com> 

> Hi,
> &nbsp;&nbsp; There are groups for AVR and ATMega which I
> would like to share
> with all.
> 
> http://groups.yahoo.com/group/AVR_Microcontroller
> http://groups.yahoo.com/group/ATMega_Microcontroller
> 
> Bye
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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Zack Widup wrote:
> On Tue, 29 Mar 2005, Ralph Hilton wrote:
> 
> 
>>On Mon, 28 Mar 2005 18:08:20 -0000 you wrote:
>>
>>
>>>Hi,
>>>   There are groups for AVR and ATMega which I would like to share
>>>with all.
>>>
>>>http://groups.yahoo.com/group/AVR_Microcontroller
>>>http://groups.yahoo.com/group/ATMega_Microcontroller
>>
>>Too many groups get to be a pain!
>>--
>>Ralph Hilton
> 
> 
> Yes, that's for sure.  I recall when I started using AVR's I looked for 
> groups on Yahoogroups and came up with half a dozen or so.  I picked a 
> couple and joined them.  I eventually ended up on this group, which is the 
> only one with much activity.
> 
> There is another one, AVR-DEV, set up by Diz W8DIZ of Parts and Kits 
> (http://www.partsandkits.com).  He has been trying to develop a ham radio 
> transceiver called the MultiPIG with an AVR controlling an AD9850 DSP 
> chip.  
> 
> The last I heard from Diz, he had all but given up on the AD9850 for 
> wide-frequency use because the unwanted spurs on the output were causing 
> all sorts of intermod and noise floor problems and he wasn't getting the 
> desired result.  
> 
> I've used the AD9850 in a very narrow-band receiver with a narrow filter 
> on the output (500 kHz wide at 12 MHz) and it seemed to do a lot better, 
> but if you're trying to use the 9850 as the LO for the entire shortwave 
> spectrum this becomes a big problem.
> 
> So I haven't seen a posting to that group in months, either.
> 
> This is the best AVR group as far as I'm concerened.
> 
> Zack W9SZ

Multiple groups thin out the expertise. I could have told yas years ago
about receiver design, dds spurs, and what to do with'em.

Hi Russell,

Can you tell me more?

Zack W9SZ

On Wed, 30 Mar 2005, Russell Shaw wrote:

> 
> Multiple groups thin out the expertise. I could have told yas years ago
> about receiver design, dds spurs, and what to do with'em.
>

Zack Widup wrote:
> 
> Hi Russell,
> 
> Can you tell me more?
> 
> Zack W9SZ
> 
> On Wed, 30 Mar 2005, Russell Shaw wrote:
> 
>>Multiple groups thin out the expertise. I could have told yas years ago
>>about receiver design, dds spurs, and what to do with'em.

The spurs are caused by capacitive spikes generated by each dac pin. The
lowest LSB has an equal glitch level as the MSB, so the biggest total
glitch energy happens when most of the pins switch in the same direction.
When an output pin switches, the small spike of capacitive current also
puts a pulse on the grounding bond wires of the dac chip, which feeds
thru to the other output pins too.
With this, you can make a program that computes the spur levels for any dds
clock frequency and output frequency setting. Then you can find a band
where the spurs are low. Eg, you might use a dds clock of 50MHz and find
a 100kHz BW low-spur band around 1-2MHz. You then mix this into a conventional
pll system, so that the dds gives you the sub 100kHz step capability, and
the conventional pll runs with a 100kHz reference. The conventional pll
is used as the first LO, such as 45-75MHz for a 0-30MHz HF receiver.
This sort of circuitry involves a fair bit of filtering and mixing
that can take a while to design for the uninitiated.

Without the dac problems, a properly designed dds only has spurs
due to the usual finite bit quantization resolution. This can be
made arbitrarily small inside a dsp program, but in hardware, the
dac problems take over.