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DebugWire question..

DebugWire question..

2005-12-28 by Micah Stevens

Hi, 
 
 I'm working on a design utilizing an ATMega88, and it's pretty full up. The 
DebugWire interface is what I would like to use to program the chip in 
production, but to turn on that interface, apparently you need to set 
something using the serial interface. 
 
 However, I need to use one pin of the serial interface(MOSI I think) as a PWM 
output. I'm concerned that during normal operation, any sort of header would 
just turn into an antenna at the PWM frequencies I'm using. 
 
 Has anyone run into this and discovered a convenient way to do double duty in 
this scenario, or am I hosed? 
 
 I'm not opposed to going to just a Serial programmer, but the same situation 
applies there as the same pin is being used. 
 
 Thank you for any suggestions, 
 -Micah

Re: [AVR-Chat] DebugWire question..

2005-12-28 by Brian Dean

On Tue, Dec 27, 2005 at 09:59:53PM -0800, Micah Stevens wrote:

> However, I need to use one pin of the serial interface(MOSI I think)
> as a PWM output. I'm concerned that during normal operation, any
> sort of header would just turn into an antenna at the PWM
> frequencies I'm using.

Unless you are PWM'ing on the order of around 10 GHz, I think you will
be OK.

-Brian
-- 
Brian Dean
ATmega128 based MAVRIC controllers
http://www.bdmicro.com/

Re: [AVR-Chat] DebugWire question..

2005-12-28 by Micah Stevens

Wow, at 10Ghz, yes, I'd agree. I'll try it and hook up the spec an, and see 
what I get I guess. Thanks for the reply, makes me feel better about it!

-Micah
Show quoted textHide quoted text
On Wednesday 28 December 2005 8:48 am, Brian Dean wrote:
>  On Tue, Dec 27, 2005 at 09:59:53PM -0800, Micah Stevens wrote:
>  > However, I need to use one pin of the serial interface(MOSI I think)
>  > as a PWM output. I'm concerned that during normal operation, any
>  > sort of header would just turn into an antenna at the PWM
>  > frequencies I'm using.
>
>  Unless you are PWM'ing on the order of around 10 GHz, I think you will
>  be OK.
>
>  -Brian
>  --
>  Brian Dean
>  ATmega128 based MAVRIC controllers
>  http://www.bdmicro.com/
>
>
>
> SPONSORED LINKS
> Atmel avr   Microcontrollers   Intel microprocessors
>   Pic microcontrollers
>
>
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>
>
>  Visit your group "AVR-Chat" on the web.
>  
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Re: [AVR-Chat] DebugWire question..

2005-12-28 by John Samperi

At 04:59 PM 28/12/2005, you wrote
>The DebugWire interface is what I would like to use to program the chip in
>production, but to turn on that interface, apparently you need to set
>something using the serial interface.

Doesn't Debugwire use just the Reset pin? I haven't used it but
from what I understand you JUST need that pin which will need
to be setup for it (i.e. disable the Reset function)



Regards

John Samperi

********************************************************
Ampertronics Pty. Ltd.
11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
Tel. (02) 9674-6495       Fax (02) 9674-8745
Email: john@ampertronics.com.au
Website  http://www.ampertronics.com.au
*Electronic Design * Custom Products * Contract Assembly
********************************************************

Re: [AVR-Chat] DebugWire question..

2005-12-28 by Micah Stevens

Yes, but the part has that interface turned off by default from the factory, 
so you need the serial interface to turn it on before you can use it.

I'm sure they did this so that the reset pin is just a reset pin by default, 
but I think they could of done this smarter.. *Shrug* 

-Micah 
Show quoted textHide quoted text
On Wednesday 28 December 2005 2:00 pm, John Samperi wrote:
>  At 04:59 PM 28/12/2005, you wrote
>
>  >The DebugWire interface is what I would like to use to program the chip
>  > in production, but to turn on that interface, apparently you need to set
>  > something using the serial interface.
>
>  Doesn't Debugwire use just the Reset pin? I haven't used it but
>  from what I understand you JUST need that pin which will need
>  to be setup for it (i.e. disable the Reset function)
>
>
>
>  Regards
>
>  John Samperi
>
>  ********************************************************
>  Ampertronics Pty. Ltd.
>  11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
>  Tel. (02) 9674-6495       Fax (02) 9674-8745
>  Email: john@ampertronics.com.au
>  Website  http://www.ampertronics.com.au
>  *Electronic Design * Custom Products * Contract Assembly
>  ********************************************************
>
>
>
>
> YAHOO! GROUPS LINKS
>
>
>  Visit your group "AVR-Chat" on the web.
>  
>  To unsubscribe from this group, send an email to:
>  AVR-Chat-unsubscribe@yahoogroups.com
>  
>  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

Re: [AVR-Chat] DebugWire question..

2005-12-28 by Micah Stevens

Roger that. Thanks!
Show quoted textHide quoted text
On Wednesday 28 December 2005 3:08 pm, MuRaT KaRaDeNiZ wrote:
>  Hello Micah,
>
>  Though not an Atmel AVR device, I've seen a case where is an unconnected
>  serial port header was picking up electromagnetic interference in a
>  harsh industrial environment. This was a susceptibility case, but  in
>  the final product i'll consider a second hardware checkpoint before
>  flashing the eeprom with the incoming bytes :)
>
>  If you want to feel safe, put a rise time limiting series resistor close
>  to the uC's pin, it will help you limit the frequency content of the
>  net. It's not just the header but also the pcb trace can act as an
>  antenna and radiate/pick up. Doing this also makes your power rails
>  inside the uC cleaner. Motorola HCS08 devices have for example
>  programmable rise time for the IO, you can select between strong/weak
>  etc. push/pull operation.
>
>
>  Regards
>
>  Murat Karadeniz
>  http://www.onlinefavbar.com/mukas/
>
>
>
>
>  -----Original Message-----
>  From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On
>  Behalf Of Micah Stevens
>  Sent: Wednesday, December 28, 2005 9:58 PM
>  To: AVR-Chat@yahoogroups.com
>  Subject: Re: [AVR-Chat] DebugWire question..
>
>
>
>  Wow, at 10Ghz, yes, I'd agree. I'll try it and hook up the spec an, and
>  see
>  what I get I guess. Thanks for the reply, makes me feel better about it!
>
>  -Micah
>
>  On Wednesday 28 December 2005 8:48 am, Brian Dean wrote:
>  >  On Tue, Dec 27, 2005 at 09:59:53PM -0800, Micah Stevens wrote:  >
>  > However, I need to use one pin of the serial interface(MOSI I think) 
>  >
>  > > as a PWM output. I'm concerned that during normal operation, any  >
>  >
>  > sort of header would just turn into an antenna at the PWM  >
>  > frequencies I'm using.
>  >
>  >  Unless you are PWM'ing on the order of around 10 GHz, I think you
>  > will  be OK.
>  >
>  >  -Brian
>  >  --
>  >  Brian Dean
>  >  ATmega128 based MAVRIC controllers
>  >  http://www.bdmicro.com/
>  >
>  >
>  >
>  > SPONSORED LINKS
>  > Atmel avr   Microcontrollers   Intel microprocessors
>  >   Pic microcontrollers
>  >
>  >
>  > YAHOO! GROUPS LINKS
>  >
>  >
>  >  Visit your group "AVR-Chat" on the web.
>  >  
>  >  To unsubscribe from this group, send an email to:
>  >  AVR-Chat-unsubscribe@yahoogroups.com
>  >  
>  >  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
>
>  Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
> SPONSORED LINKS
> Atmel avr   Microcontrollers   Intel microprocessors
>   Pic microcontrollers
>
>
> YAHOO! GROUPS LINKS
>
>
>  Visit your group "AVR-Chat" on the web.
>  
>  To unsubscribe from this group, send an email to:
>  AVR-Chat-unsubscribe@yahoogroups.com
>  
>  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

RE: [AVR-Chat] DebugWire question..

2005-12-28 by MuRaT KaRaDeNiZ

Hello Micah,

Though not an Atmel AVR device, I've seen a case where is an unconnected
serial port header was picking up electromagnetic interference in a
harsh industrial environment. This was a susceptibility case, but  in
the final product i'll consider a second hardware checkpoint before
flashing the eeprom with the incoming bytes :)

If you want to feel safe, put a rise time limiting series resistor close
to the uC's pin, it will help you limit the frequency content of the
net. It's not just the header but also the pcb trace can act as an
antenna and radiate/pick up. Doing this also makes your power rails
inside the uC cleaner. Motorola HCS08 devices have for example
programmable rise time for the IO, you can select between strong/weak
etc. push/pull operation.


Regards

Murat Karadeniz
http://www.onlinefavbar.com/mukas/
Show quoted textHide quoted text
-----Original Message-----
From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On
Behalf Of Micah Stevens
Sent: Wednesday, December 28, 2005 9:58 PM
To: AVR-Chat@yahoogroups.com
Subject: Re: [AVR-Chat] DebugWire question..



Wow, at 10Ghz, yes, I'd agree. I'll try it and hook up the spec an, and
see 
what I get I guess. Thanks for the reply, makes me feel better about it!

-Micah


On Wednesday 28 December 2005 8:48 am, Brian Dean wrote:
>  On Tue, Dec 27, 2005 at 09:59:53PM -0800, Micah Stevens wrote:  > 
> However, I need to use one pin of the serial interface(MOSI I think)  
> > as a PWM output. I'm concerned that during normal operation, any  > 
> sort of header would just turn into an antenna at the PWM  > 
> frequencies I'm using.
>
>  Unless you are PWM'ing on the order of around 10 GHz, I think you 
> will  be OK.
>
>  -Brian
>  --
>  Brian Dean
>  ATmega128 based MAVRIC controllers
>  http://www.bdmicro.com/
>
>
>
> SPONSORED LINKS
> Atmel avr   Microcontrollers   Intel microprocessors
>   Pic microcontrollers
>
>
> YAHOO! GROUPS LINKS
>
>
>  Visit your group "AVR-Chat" on the web.
>  
>  To unsubscribe from this group, send an email to:
>  AVR-Chat-unsubscribe@yahoogroups.com
>  
>  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.



 
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