AVR-Chat

Folks, i have a really bit problem i cant understand.
I am using ATMEGA32L on a 7805 powered board but i cant make it run 
or even reset. The chip is proprerly powered , i tried a lot of reset 
circuits, of course including the one provided by atmel, but there is 
no way it runs by itself. The thing comes when a tie an external 
voltage source to the reset pin (ex. an ISP programmer). Everything 
seems to work fine, even the reset circuitry, but as soon as i take 
out this external reset source, the chip halts. I dont have a clue 
about what this could be. I am using internal clock source and tried 
1 and 8 MHZ. 
Ever happenned to you?? Suggestions??? ANY CLUEEEE!??????


Thanks 
Javier

Javier,

> The thing comes when a tie an external
> voltage source to the reset pin (ex. an ISP programmer). Everything
> seems to work fine, even the reset circuitry, but as soon as i take
> out this external reset source, the chip halts. I dont have a clue
> about what this could be.

Try connecting a pull up resistor between the Reset pin and the 5V supply,
that should do it.
You can't leave this pin floating, it needs to be connected to a 'high' for
it to work.
If you plan to use the ISP sometimes then use a 10K resistor and all will be
well.

Paul

Try a new CPU.  You should be able to float the Reset line and have it run
fine.  There is an internal 50k pull-up inside the chip.

-----Original Message-----
From: Paul Maddox

Javier,

> The thing comes when a tie an external
> voltage source to the reset pin (ex. an ISP programmer). Everything
> seems to work fine, even the reset circuitry, but as soon as i take
> out this external reset source, the chip halts. I dont have a clue
> about what this could be.

Try connecting a pull up resistor between the Reset pin and the 5V supply,
that should do it.
You can't leave this pin floating, it needs to be connected to a 'high' for
it to work.
If you plan to use the ISP sometimes then use a 10K resistor and all will be
well.

You may have problems in the software that runs immediately
after RESET. Try some software delay after RESET.

	Mark Jordan

On 2 Feb 2005 at 11:12, Javier Fiasche wrote:

> 
> Thanks, but i also tried with a 10k, 4.7k and 1 k pull ups, and even by connecting reset line 
> directly to VCC and any of that worked
> The problem seems to be other
> Thanks again
> Javier
> 
> -----Mensaje original-----
> De: Paul Maddox [mailto:P.Maddox@signal.qinetiq.com]
> Enviado el: Miércoles, 02 de Febrero de 2005 10:57 a.m.
> Para: AVR-Chat@yahoogroups.com
> Asunto: Re: [AVR-Chat] Bootup/reset very big problem
> 
> Javier,
> 
> > The thing comes when a tie an external
> > voltage source to the reset pin (ex. an ISP programmer). Everything
> > seems to work fine, even the reset circuitry, but as soon as i take
> > out this external reset source, the chip halts. I dont have a clue
> > about what this could be.
> 
> Try connecting a pull up resistor between the Reset pin and the 5V supply,
> that should do it.
> You can't leave this pin floating, it needs to be connected to a 'high' for
> it to work.
> If you plan to use the ISP sometimes then use a 10K resistor and all will be
> well.
> 
> Paul
> 
> 
> 
> Yahoo! Groups Links
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> 
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> Internet para todos.

--- In AVR-Chat@yahoogroups.com, "Javier Fiasche" <jfiasche@t...> 
wrote:
> the 7805 already has .33uf and 100 uf capacitors, and every ic has 
a 100nf
> bypass capacitor near it, Any other suggestions, i am about to 
break the
> board!!, jejeje :-(

Is the oscillator running - check with a scope.

Leon

On Thu, 3 Feb 2005 08:17:31 -0300, Javier Fiasche <jfiasche@tutopia.com>  
wrote:

> the 7805 already has .33uf and 100 uf capacitors, and every ic has a  
> 100nf bypass capacitor near it, Any other suggestions, i am about to  
> break the board!!, jejeje :-(


When you connect reset to 5V it must run, if it doesn't the chip is faulty  
or your software is faulty.
Get a voltmeter and check the supply and reset pins.

ST

Javier Fiasche wrote:

> the 7805 already has .33uf and 100 uf capacitors, and every ic has a 
> 100nf bypass capacitor near it, Any other suggestions, i am about to 
> break the board!!, jejeje :-(

I would suspect the uC :(

Regards,

Kat.

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Javier Fiasche wrote:

> As i use the external reset source (ex ISP programmer,) , i works almost 
> fine(LCd, etc works), the problem is when i remove the isp, the cpu 
> seems to halt. I am using internal clock so i cant check the oscilator.
> If i powwer on the board withoput the isp, it never stars to run
> Thanks
>  
> Javier

Check the +5V at the uC (make sure you are not powering it by the ISP)

Check the reset line is +5V

THAT IS ALL IT CAN BE !!!!!!

Regards,

Kat.


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IM: Yahoo: PinkyDwaggy  MSN: katinka@kaqelectronics.dyndns.org
For Everything Electronics     Phone: 0419 923 731
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On Thu, 3 Feb 2005 08:53:00 -0300, Javier Fiasche <jfiasche@tutopia.com>  
wrote:

> As i use the external reset source (ex ISP programmer,) , i works almost  
> fine(LCd, etc works), the problem is when i remove the isp, the cpu  
> seems to halt. I am using internal clock so i cant check the  
> oscilator.If i powwer on the board withoput the isp, it never stars to  
> runThanks Javier

Then check if you have 5V at the reset pin (and supply while you are at  
it) or not, please.

ST

I have:

		all vcc pins 5.05v
		rst pin	4.89 v
 and the device is at mega32l

javier


-----Mensaje original-----
De: Stefan Trethan [mailto:stefan_trethan@gmx.at]
Enviado el: Jueves, 03 de Febrero de 2005 09:24 a.m.
Para: AVR-Chat@yahoogroups.com
Asunto: Re: [AVR-Chat] Re: Bootup/reset very big problem



On Thu, 3 Feb 2005 08:53:00 -0300, Javier Fiasche <jfiasche@tutopia.com>
wrote:

> As i use the external reset source (ex ISP programmer,) , i works almost
> fine(LCd, etc works), the problem is when i remove the isp, the cpu
> seems to halt. I am using internal clock so i cant check the
> oscilator.If i powwer on the board withoput the isp, it never stars to
> runThanks Javier

Then check if you have 5V at the reset pin (and supply while you are at
it) or not, please.

ST



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On Thu, 3 Feb 2005 09:43:51 -0300, Javier Fiasche <jfiasche@tutopia.com>  
wrote:

>
>
> I have:
>
> 		all vcc pins 5.05v
> 		rst pin	4.89 v
>  and the device is at mega32l
>
> javier
>

then there is some other fault.
Maybe the programmer you use doesn't change reset after all, but maybe it  
has pullups or something that cause other signals to work only if it is  
connected.

ST

On Thu, 3 Feb 2005, Stefan Trethan wrote:

> 
> On Thu, 3 Feb 2005 09:43:51 -0300, Javier Fiasche <jfiasche@tutopia.com>  
> wrote:
> 
> >
> >
> > I have:
> >
> > 		all vcc pins 5.05v
> > 		rst pin	4.89 v
> >  and the device is at mega32l
> >
> > javier
> >
> 
> then there is some other fault.
> Maybe the programmer you use doesn't change reset after all, but maybe it  
> has pullups or something that cause other signals to work only if it is  
> connected.
> 
> ST
> 

Hi Javier,

What programmer are you using?

The one thing I had trouble with at first with my STK-500 was getting used 
to setting the configuration bits for the oscillator.  For some reason it 
started out with default settings and if I toggled between the config 
window and the program window with AVR Studio, it reset my config bits to 
default.  Or at least that's what I think happened.  That was with my 
first few programming attempts, which didn't work until I got the config 
bits set exactly the way I wanted them.  Then everything was fine.

But the configuration bits have to be set correctly for the type of 
oscillator you're using, or your programmed AVR will just sit there like a 
stone. That's pretty frustrating!

Zack

Ok, thanks Zack, i am using a programmer called Ser2conmini, its uses Com
port control  and data signals, i made it myself
The configuration bits are configured ok, the cpu runs, but only with an
external power source connected to the rst line. If i just plug the
programmer to my target board it begins o run, but as i disconnect it, it
halts. Same happens if i do not plug the isp at all. I think it has
something to do with RST
-----Mensaje original-----
De: Zack Widup [mailto:w9sz@prairienet.org]
Enviado el: Jueves, 03 de Febrero de 2005 11:13 a.m.
Para: AVR-Chat@yahoogroups.com
Asunto: Re: [AVR-Chat] Re: Bootup/reset very big problem


On Thu, 3 Feb 2005, Stefan Trethan wrote:

>
> On Thu, 3 Feb 2005 09:43:51 -0300, Javier Fiasche <jfiasche@tutopia.com>
> wrote:
>
> >
> >
> > I have:
> >
> >             all vcc pins 5.05v
> >             rst pin      4.89 v
> >  and the device is at mega32l
> >
> > javier
> >
>
> then there is some other fault.
> Maybe the programmer you use doesn't change reset after all, but maybe it
> has pullups or something that cause other signals to work only if it is
> connected.
>
> ST
>

Hi Javier,

What programmer are you using?

The one thing I had trouble with at first with my STK-500 was getting used
to setting the configuration bits for the oscillator.  For some reason it
started out with default settings and if I toggled between the config
window and the program window with AVR Studio, it reset my config bits to
default.  Or at least that's what I think happened.  That was with my
first few programming attempts, which didn't work until I got the config
bits set exactly the way I wanted them.  Then everything was fine.

But the configuration bits have to be set correctly for the type of
oscillator you're using, or your programmed AVR will just sit there like a
stone. That's pretty frustrating!

Zack



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On Thu, 3 Feb 2005 11:36:54 -0300, Javier Fiasche <jfiasche@tutopia.com>  
wrote:

> Ok, thanks Zack, i am using a programmer called Ser2conmini, its uses  
> Com port control  and data signals, i made it myselfThe configuration  
> bits are configured ok, the cpu runs, but only with an external power  
> source connected to the rst line. If i just plug the programmer to my  
> target board it begins o run, but as i disconnect it, it halts. Same  
> happens if i do not plug the isp at all. I think it has something to do  
> with RST


Javier,

If you measure the voltage at RST with and without the programmer, and  
they are both logic high, it makes no sense that it has to do with RST.  
The current has no tag, the atmel can't tell where it came from.

Do you have a schematic? i still think a pullup or something is on another  
pin.

ST

Here goes the SCH.............
I someone realises what ist wrong, please tell me

Thanks

Javier



-----Mensaje original-----
De: Stefan Trethan [mailto:stefan_trethan@gmx.at]
Enviado el: Jueves, 03 de Febrero de 2005 12:06 p.m.
Para: AVR-Chat@yahoogroups.com
Asunto: Re: [AVR-Chat] Re: Bootup/reset very big problem



On Thu, 3 Feb 2005 11:36:54 -0300, Javier Fiasche <jfiasche@tutopia.com>
wrote:

> Ok, thanks Zack, i am using a programmer called Ser2conmini, its uses
> Com port control  and data signals, i made it myselfThe configuration
> bits are configured ok, the cpu runs, but only with an external power
> source connected to the rst line. If i just plug the programmer to my
> target board it begins o run, but as i disconnect it, it halts. Same
> happens if i do not plug the isp at all. I think it has something to do
> with RST


Javier,

If you measure the voltage at RST with and without the programmer, and
they are both logic high, it makes no sense that it has to do with RST.
The current has no tag, the atmel can't tell where it came from.

Do you have a schematic? i still think a pullup or something is on another
pin.

ST



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At 10:20 AM 2/3/2005, Javier Fiasche wrote:
>Here goes the SCH.............
>I someone realises what ist wrong, please tell me


Don't post binaries to everyone.  You just sent out hundreds of emails with 
attached files that almost nobody can open since they likely don't have the 
software you used to create them.

Upload the files to the files area, and tell people where they are.
Further, a PDF or BMP/GIF of the schematic would be a lot more useful, and 
essentially everyone could open it.

Could you post here your initialization routine?
	I suspect your software is doing something wrong.

	Mark Jordan

On 3 Feb 2005 at 9:43, Javier Fiasche wrote:

> 
> 
> I have:
> 
> 		all vcc pins 5.05v
> 		rst pin	4.89 v
>  and the device is at mega32l
> 
> javier
> 
> 
> -----Mensaje original-----
> De: Stefan Trethan [mailto:stefan_trethan@gmx.at]
> Enviado el: Jueves, 03 de Febrero de 2005 09:24 a.m.
> Para: AVR-Chat@yahoogroups.com
> Asunto: Re: [AVR-Chat] Re: Bootup/reset very big problem
> 
> 
> 
> On Thu, 3 Feb 2005 08:53:00 -0300, Javier Fiasche <jfiasche@tutopia.com>
> wrote:
> 
> > As i use the external reset source (ex ISP programmer,) , i works almost
> > fine(LCd, etc works), the problem is when i remove the isp, the cpu
> > seems to halt. I am using internal clock so i cant check the
> > oscilator.If i powwer on the board withoput the isp, it never stars to
> > runThanks Javier
> 
> Then check if you have 5V at the reset pin (and supply while you are at
> it) or not, please.
> 
> ST
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 
> 
> 
> ______________________________
> Visita http://www.tutopia.com y comienza a navegar más rápido en Internet. Tutopia es Internet para todos.
> 
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
>

I didn't find the STACK initialization.
	And the Watchdog, too.

	Mark Jordan

On 3 Feb 2005 at 12:56, Javier Fiasche wrote:

> 
> Here goes the inicialization routine
> 
> 
> void init_mega32(void)
> { 
> 
> #ifndef DEGUB 
>  MCUCSR|=0x80;// Disable JTAG
> #endif 
> 
> // Port A initialization
> PORTA=0b00001000;
> DDRA=0b00001000;
>  // Port B initialization
>  DDRB=0b00000000;
>  PORTB=0b00001111;
>  // Port C initialization
> DDRC=0b10110000;
> PORTC=0b10000000;
> // Port D initialization
> DDRD=0b11100000;
> PORTD=0b00000000;
> 
> // Timer/Counter 0 initialization
> // Clock source: System Clock
> // Clock value: Timer 0 Stopped
> // Mode: Normal top=FFh
> // OC0 output: Disconnected
> TCCR0=0x00;
> TCNT0=0x00;
> OCR0=0x00;
> 
> // Timer/Counter 1 initialization
> // Clock source: System Clock
> // Clock value: Timer 1 Stopped
> // Mode: Normal top=FFFFh
> // OC1A output: Discon.
> // OC1B output: Discon.
> // Noise Canceler: Off
> // Input Capture on Falling Edge
> TCCR1A=0x00;
> TCCR1B=0x00;
> TCNT1H=0x00;
> TCNT1L=0x00;
> OCR1AH=0x00;
> OCR1AL=0x00;
> OCR1BH=0x00;
> OCR1BL=0x00;
> 
> // Timer/Counter 2 initialization
> // Clock source: System Clock
> // Clock value: Timer 2 Stopped
> // Mode: Normal top=FFh
> // OC2 output: Disconnected
> ASSR=0x00;
> TCCR2=0x00;
> TCNT2=0x00;
> OCR2=0x00;
> 
> // External Interrupt(s) initialization
> // INT0: Off
> // INT1: Off
> // INT2: Off
> GICR|=0x00;
> MCUCR=0x00;
> 
> // Timer(s)/Counter(s) Interrupt(s) initialization
> TIMSK=0x00;
> 
> // USART initialization
> // Communication Parameters: 8 Data, 1 Stop, No Parity
> // USART Receiver: On
> // USART Transmitter: On
> // USART Mode: Asynchronous
> // USART Baud rate: 9600 (Double Speed Mode)
> UCSRA=0x02;
> UCSRB=0x18;
> UCSRC=0x86;
> UBRRH=0x00;
> UBRRL=0x0C;
> 
> // Analog Comparator initialization
> // Analog Comparator: Off
> // Analog Comparator Input Capture by Timer/Counter 1: Off
> // Analog Comparator Output: Off
> ACSR=0x80;
> SFIOR=0x00;
> 
> } 
> 
> 
> 
> Any ideas???
> 
> 
> thanks javier

I belive stack inicialization is made by Codevision C compiler. Watchdog
isnt used at this moment. It should be turned off

Thanks
Javier

-----Mensaje original-----
De: Mark Jordan [mailto:mark@cpovo.net]
Enviado el: Jueves, 03 de Febrero de 2005 01:14 p.m.
Para: AVR-Chat@yahoogroups.com
Asunto: RE: [AVR-Chat] Re: Bootup/reset very big problem



      I didn't find the STACK initialization.
      And the Watchdog, too.

      Mark Jordan

On 3 Feb 2005 at 12:56, Javier Fiasche wrote:

>
> Here goes the inicialization routine
>
>
> void init_mega32(void)
> {
>
> #ifndef DEGUB
>  MCUCSR|=0x80;// Disable JTAG
> #endif
>
> // Port A initialization
> PORTA=0b00001000;
> DDRA=0b00001000;
>  // Port B initialization
>  DDRB=0b00000000;
>  PORTB=0b00001111;
>  // Port C initialization
> DDRC=0b10110000;
> PORTC=0b10000000;
> // Port D initialization
> DDRD=0b11100000;
> PORTD=0b00000000;
>
> // Timer/Counter 0 initialization
> // Clock source: System Clock
> // Clock value: Timer 0 Stopped
> // Mode: Normal top=FFh
> // OC0 output: Disconnected
> TCCR0=0x00;
> TCNT0=0x00;
> OCR0=0x00;
>
> // Timer/Counter 1 initialization
> // Clock source: System Clock
> // Clock value: Timer 1 Stopped
> // Mode: Normal top=FFFFh
> // OC1A output: Discon.
> // OC1B output: Discon.
> // Noise Canceler: Off
> // Input Capture on Falling Edge
> TCCR1A=0x00;
> TCCR1B=0x00;
> TCNT1H=0x00;
> TCNT1L=0x00;
> OCR1AH=0x00;
> OCR1AL=0x00;
> OCR1BH=0x00;
> OCR1BL=0x00;
>
> // Timer/Counter 2 initialization
> // Clock source: System Clock
> // Clock value: Timer 2 Stopped
> // Mode: Normal top=FFh
> // OC2 output: Disconnected
> ASSR=0x00;
> TCCR2=0x00;
> TCNT2=0x00;
> OCR2=0x00;
>
> // External Interrupt(s) initialization
> // INT0: Off
> // INT1: Off
> // INT2: Off
> GICR|=0x00;
> MCUCR=0x00;
>
> // Timer(s)/Counter(s) Interrupt(s) initialization
> TIMSK=0x00;
>
> // USART initialization
> // Communication Parameters: 8 Data, 1 Stop, No Parity
> // USART Receiver: On
> // USART Transmitter: On
> // USART Mode: Asynchronous
> // USART Baud rate: 9600 (Double Speed Mode)
> UCSRA=0x02;
> UCSRB=0x18;
> UCSRC=0x86;
> UBRRH=0x00;
> UBRRL=0x0C;
>
> // Analog Comparator initialization
> // Analog Comparator: Off
> // Analog Comparator Input Capture by Timer/Counter 1: Off
> // Analog Comparator Output: Off
> ACSR=0x80;
> SFIOR=0x00;
>
> }
>
>
>
> Any ideas???
>
>
> thanks javier




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Dave VanHorn wrote:
> 
> At 10:20 AM 2/3/2005, Javier Fiasche wrote:
> >Here goes the SCH.............
> >I someone realises what ist wrong, please tell me
> 
> Don't post binaries to everyone.  You just sent out hundreds of emails with
> attached files that almost nobody can open since they likely don't have the
> software you used to create them.
> 
> Upload the files to the files area, and tell people where they are.
> Further, a PDF or BMP/GIF of the schematic would be a lot more useful, and
> essentially everyone could open it.
> 

Well I can and did. If you look at the AVR component and count the pins, you'll see
that pins 17, 18, 38 and 39 are missing. Atmel seems to thing these pins should be 
connected to Vcc and GND. It might help...

Bruce

Thanks a lot bruce, i did had that in mind while designning , but i measured
the voltage at those pins and it is VCC and GND
Thanks a lot, i'll figure the way to connect them
Javier

-----Mensaje original-----
De: Bruce Parham [mailto:obparham@jpl.nasa.gov]
Enviado el: Jueves, 03 de Febrero de 2005 01:28 p.m.
Para: AVR-Chat@yahoogroups.com
Asunto: Re: [AVR-Chat] Re: Bootup/reset very big problem




Dave VanHorn wrote:
>
> At 10:20 AM 2/3/2005, Javier Fiasche wrote:
> >Here goes the SCH.............
> >I someone realises what ist wrong, please tell me
>
> Don't post binaries to everyone.  You just sent out hundreds of emails
with
> attached files that almost nobody can open since they likely don't have
the
> software you used to create them.
>
> Upload the files to the files area, and tell people where they are.
> Further, a PDF or BMP/GIF of the schematic would be a lot more useful, and
> essentially everyone could open it.
>

Well I can and did. If you look at the AVR component and count the pins,
you'll see
that pins 17, 18, 38 and 39 are missing. Atmel seems to thing these pins
should be
connected to Vcc and GND. It might help...

Bruce


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On Thu, 03 Feb 2005 08:27:55 -0800, Bruce Parham <obparham@jpl.nasa.gov>  
wrote:

>
> Well I can and did. If you look at the AVR component and count the pins,  
> you'll see
> that pins 17, 18, 38 and 39 are missing. Atmel seems to thing these pins  
> should be
> connected to Vcc and GND. It might help...
> Bruce


orcad has power pins not visible per default.


ST

Stefan Trethan wrote:
> 
> On Thu, 03 Feb 2005 08:27:55 -0800, Bruce Parham <obparham@jpl.nasa.gov>
> wrote:
> 
> >
> > Well I can and did. If you look at the AVR component and count the pins,
> > you'll see
> > that pins 17, 18, 38 and 39 are missing. Atmel seems to thing these pins
> > should be
> > connected to Vcc and GND. It might help...
> > Bruce
> 
> orcad has power pins not visible per default.
> 
> ST
> 

Yes and it a feature that should never be used because of this exact kind of problem.

If a component has too many pins to fit nicely on a component section, you can make it a
heterogeneous part and put signals in one or more sections and power/gnd pins in 
another or other sections. Trust me on this, my Xilinx parts library has parts
with over 1500 pins. No way would that be possible on a single section - so divide
and conquer...

Bruce

> Javier Fiasche wrote:
> 
> Thanks a lot bruce, i did had that in mind while designning , but i measured the voltage at those pins and it is VCC and GND
> Thanks a lot, i'll figure the way to connect them
> Javier

No problem, glad to help. But, yes, ALL of the power and ground pins must be connected
and it is recommended to have bypass caps on each pair as close to the package as
possible.

Bruce

>
>Well I can and did.

I'm glad that someone could use them, but the point remains, binaries don't 
go to the list, they go in the files area.

>  If you look at the AVR component and count the pins, you'll see
>that pins 17, 18, 38 and 39 are missing. Atmel seems to thing these pins 
>should be
>connected to Vcc and GND. It might help...

His power pins may be hidden, or actually not connected.
I used to use hidden power pins, but I gave it up, I want them shown, along 
with the bypass caps.
Saves much confusion.

On Thu, 03 Feb 2005 09:09:01 -0800, Bruce Parham <obparham@jpl.nasa.gov>  
wrote:

>> orcad has power pins not visible per default.
>>
>> ST
>>
> Yes and it a feature that should never be used because of this exact  
> kind of problem.
> Bruce


I never use it anyway, annoys me to no end.
i don't mind the additional pins.


ST

Bruce Parham said:
>
>
> Well I can and did. If you look at the AVR component and count the pins,
> you'll see that pins 17, 18, 38 and 39 are missing. Atmel seems to thing
> these pins should be  connected to Vcc and GND. It might help...

I never could find the files.  It's fairly common practice for most
schematic capture programs not to clutter the schematic with the power and
ground pins though...  It's often a good idea to verify them on the
netlist before you order the board.

Mike

Just a few thoughts..
 
A schematic is (or can be) an art that reveals a lot about the person who
draws it, how organized the person is, if the person is artistic etc. 
I always look at my schematics like artwork and it's up most important that
not only I but also the persons that are to review them later for possible
repair or what ever can understand them right away.
 
http://212.242.218.104/LDR.pdf
 
It is possible to add power net's without compromising the schematic artwork
as Bruce mentioned.
 
Regards
Lasse Madsen
 
 
 
  _____  

From: Mike Murphree [mailto:mike@tropo.org] 
Sent: 3. februar 2005 18:21
To: AVR-Chat@yahoogroups.com
Subject: Re: [AVR-Chat] Re: Bootup/reset very big problem
 
Bruce Parham said:
>
>
> Well I can and did. If you look at the AVR component and count the pins,
> you'll see that pins 17, 18, 38 and 39 are missing. Atmel seems to thing
> these pins should be  connected to Vcc and GND. It might help...

I never could find the files.  It's fairly common practice for most
schematic capture programs not to clutter the schematic with the power and
ground pins though...  It's often a good idea to verify them on the
netlist before you order the board.

Mike





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On Thu, 3 Feb 2005 18:27:29 +0100, Lasse Madsen  
<lasse.madsen@elektronik.dk> wrote:

> Just a few thoughts…. A schematic is (or can be) an art that reveals a  
> lot about the person who draws it, how organized the person is, if the  
> person is artistic etc. I always look at my schematics like artwork and  
> it’s up most important that not only I but also the persons that are to  
> review them later for possible repair or what ever can understand them  
> right away.

I agree that schematics are art, while layouts are much more so.
I presonally prefer it when there are not too many symbolic connections  
(arrows, names on wires).
They are good to use for global signals like power and GND, better than  
direct connection, but i hate them for signals.

It makes a schematic extremely difficult to read because you can never  
find all the connections to one point. One searches hours for the  
corresponding symbol, and you easily miss one.

Use them only when needed. (I understand that multiple page and complex  
schematics require them but the "invisible pins" schematic which caused  
the discussion had too many "loose" parts for my taste, i didn't want to  
bother reading it because it was so tedious.)

http://212.242.218.104/LDR.pdf

Well, art relies strongly on taste, De gustibus non est disputandum, no  
more comments ;-)

> It is possible to add power net’s without compromising the schematic  
> artwork as Bruce mentioned.

Of course.

ST

Lasse Madsen said:
> Just a few thoughts..
>
> A schematic is (or can be) an art that reveals a lot about the person
> who draws it, how organized the person is, if the person is artistic
> etc.  I always look at my schematics like artwork and it's up most
> important that not only I but also the persons that are to review them
> later for possible repair or what ever can understand them right away.
>
> http://212.242.218.104/LDR.pdf
>
> It is possible to add power net's without compromising the schematic
> artwork as Bruce mentioned.

I still find a necessity to check in great detail the part symbols both
for electrical connection and proper pad placement. Likewise, I verify the
netlist to make sure the proper connections were made.  It can be quite
annoying to manually place wiring to power and ground pins when you get to
456+ pin FPGA packages and you still need to verify the netlist output
anyway...

Mike

>  Trust me on this, my Xilinx parts library has parts with over 1500 pins.

I'm picturing the poor repair guy with a soldapult, on pin 300.. :)

On Thu, 03 Feb 2005 15:27:20 -0500, Dave VanHorn <dvanhorn@dvanhorn.org>  
wrote:

>>  Trust me on this, my Xilinx parts library has parts with over 1500  
>> pins.
> I'm picturing the poor repair guy with a soldapult, on pin 300..
>

I'd hope he's got a hot air unit ;-)
I have some of those rather mad xilinx ICs from a lot auction at ebay... a  
challenge for some other day. (when i have a printer with enough  
resolution for the PCB, hehe....)

ST

Dave VanHorn said:
>
>
>>  Trust me on this, my Xilinx parts library has parts with over 1500
>> pins.
>
> I'm picturing the poor repair guy with a soldapult, on pin 300.. :)

That's probably G34.  Wait is that the top view or the bottom view?
Which way is it turned?  Which one of the 16 layers did I route that
signal on?  Why did the PCB layout guy make the pad size the via size and
vica versus?

Been there, done that...

Mike

Hi
 

>I agree that schematics are art, while layouts are much more so.


Hehe totally agree!
 
>I presonally prefer it when there are not too many symbolic connections  
>(arrows, names on wires).
>They are good to use for global signals like power and GND, better than  
>direct connection, but i hate them for signals.


>It makes a schematic extremely difficult to read because you can never  
>find all the connections to one point. One searches hours for the  
>corresponding symbol, and you easily miss one.


YES ! 
 
If you have ever tried to repair any Hameg oscilloscope or just about what
else they make it's a hell frenzy to find the signals and the "funny" thing
is that for instance 
 
A signal that is called /BLAKNING on one diagram might be changed to /DUNKEL
(which is the German word for the same) on another diagram! 
And just to make matters worse the block diagram might show the same signal
as X/Y ON/OFF been there feared that at the exams . 
 

>Well, art relies strongly on taste, De gustibus non est disputandum, no  
>more comments ;-)
 
Haha! 
Yeah but in my eye's Van Gogh isn't an artist but a three year old with a
bunch of crayons and simply to much spare time.  :o)
 
Regards
Lasse M.

On Thu, 3 Feb 2005, Dave VanHorn wrote:

> 
> >  Trust me on this, my Xilinx parts library has parts with over 1500 pins.
> 
> I'm picturing the poor repair guy with a soldapult, on pin 300.. :)
> 

I once did repairs of consumer electronics and replaced a few chips with 
64 pins.  I made a tiny tip for my soldering iron out of wire (I think it 
was #22) and worked out a way of threading a fine wire up under the pins 
of the IC where they enter the body of the chip.  After removing as much 
solder as I could with solder wick, I'd pull each leg up off the board 
with the wire, starting at one end.  It took patience but it worked fine.

There's no way I'd have bothered with a 1500 pin device.  Actually, 
portable CD players, radios, etc. are so cheap now it isn't worth 
replacing the 64 pin devices any more.

Zack

On Fri, 4 Feb 2005 08:26:43 -0300, Javier Fiasche <jfiasche@tutopia.com>  
wrote:

> Well Guys i finally mannaged to make my Atmega32 run well. The thing was  
> taht the PCB manufacturer sended me a bad PCB, where net GND was split  
> and not connected to the uC. It wasnt a design problem, just a  
> manufacturing one. I wasnt able to find it before because the splited  
> part was under the TQFP atmega32.Thanks you all for the help. I found  
> the problem beacuse one of you suggested connecting all VCC and GND  
> pins, and just connecting GND , it started to run.In the future, i'll  
> make sure that the PCB is ok, and i wopnt trust in manufacturers any  
> more!!!!!!GND is something to have in mind  :-) Well regards and thanks  
> a lot to you all Javier


If you simply measure the supply pins with a digital voltmeter as i  
suggested you will easily find such faults. You must connect the gnd of  
the meter to the supply gnd.

Visual inspection of each PCB is a good idea, especially in areas where  
there will be no access later. Electrical testing is too much effort for  
me. You can never be 100% sure there are no breaks, no matter if you have  
your boards made or make them yourself. inspecting against a bright light  
source shows some faults you don't see normally (but it only works if  
there is no copper on the other side, on that spot), it also shows holes  
which are not drilled.

ST

On Fri, 4 Feb 2005, Stefan Trethan wrote:

> 
> On Fri, 4 Feb 2005 08:26:43 -0300, Javier Fiasche <jfiasche@tutopia.com>  
> wrote:
> 
> Visual inspection of each PCB is a good idea, especially in areas where  
> there will be no access later. Electrical testing is too much effort for  
> me. You can never be 100% sure there are no breaks, no matter if you have  
> your boards made or make them yourself. inspecting against a bright light  
> source shows some faults you don't see normally (but it only works if  
> there is no copper on the other side, on that spot), it also shows holes  
> which are not drilled.
> 

If you make your own boards, as I do, then it's easy to inspect them and 
repair any faults in the pattern before mounting parts.  But if you buy a 
populated board with TQFP parts already on it, it becomes more difficult.

I usually check some of the patterns with an ohmmeter on boards I make 
myself, especially those under multi-pin SMD parts that I am not going to 
want to remove after putting them on the board. Sometimes one little 
scratch goes all the way through the copper but is difficult to detect 
visually.

Zack

>
>A signal that is called /BLAKNING on one diagram might be changed to 
>/DUNKEL (which is the German word for the same) on another diagram!
>And just to make matters worse the block diagram might show the same 
>signal as X/Y ON/OFF been there feared that at the exams

For that, they deserve to be beaten.

On Fri, 4 Feb 2005 08:42:14 -0600 (CST), Zack Widup <w9sz@prairienet.org>  
wrote:

>
> If you make your own boards, as I do, then it's easy to inspect them and
> repair any faults in the pattern before mounting parts.  But if you buy a
> populated board with TQFP parts already on it, it becomes more difficult.
> I usually check some of the patterns with an ohmmeter on boards I make
> myself, especially those under multi-pin SMD parts that I am not going to
> want to remove after putting them on the board. Sometimes one little
> scratch goes all the way through the copper but is difficult to detect
> visually.
> Zack


I usually check with ohmmeter in areas where i expect possible problems,  
e.g. tight spacing or very narrow tracks. (sometimes after soldering,  
sometimes before, depending on situation).
I use toner transfer which inherently prevents breaks, but it can  
sometimes be a problem with too narrow spacing.

ST

--- In AVR-Chat@yahoogroups.com, Bruce Parham <obparham@j...> wrote:
> 
> Well I can and did. If you look at the AVR component and count the 
pins, you'll see
> that pins 17, 18, 38 and 39 are missing. Atmel seems to thing 
these pins should be 
> connected to Vcc and GND. It might help...

..it might help Javier (and others) to use the OrCAD (and Protel) 
libs from my homepage (http://www.geocities.com/_wsw_ follow the 
link to electronics/AVR there). I usually define the power pins as 
passive pins in order to be able to connect them to various power 
nets (digital/analog power etc.).

HTH,
Stefan