Очень интересует человек bezobraznic который говорит что у него отлично все работеет
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А с буквой Б нехотят везти в Киев - мол партия в 10 шт слишком маленькая
вот декларируемая разница к буковке 'B'

Если не трудно, можно опубликовать то что ответил атмел?

Message added byOleg Semyonov, 08.09.2006 14:22
Hello!

Having a self-made evaluation board with AT90PWM3, I have some issues I cannot understand. In fact, I think that those are problems with early chip revisions (my device was bought about half year ago).

1) How to identify the device revision (A or ?
My device is marked as:

90PWM3-16SQ
0540 04103AW

2) PSCnRB and PSCRV fuses.
It is said in latest datasheet that: If PSCRV fuse equals 0 (programmed), the selected PSC outputs will be forced to low state. If PSCRV fuse equals 1 (unprogrammed), the selected PSC outputs will be forced to high state.

I observe opposite situation: when all 4 bits are programmed (set to 0), I have high (Vcc) levels in outputs. If PSCRV=1 (unprogrammed), then outputs are set to low level. Is it bug, or feature, or depends on device revision?

3) BOD and Aref.
Setting the BOD fuses to have 4.3v BOD level (and 5v power supply), I have the following problem: setting via ADMUX Aref=AVcc leads to device reset. AREF pin is decoupled with external capacitor only. Without BOD enabled all is fine. I have not tried different Aref values, though.

What can be wrong?

4) Amplified ADC conversions.
I was unable to use AMP0/AMP1 differential amplified ADC inputs at all. In short, if I set the channel number up to 10 via ADMUX, then all is fine. The loop
while (!(ADCSRA & (1<<ADIF))) ;
works as expected after starting the conversion via ADSC bit in ADCSRA.

Setting the ADMUX low bits to 11 or 12 (AMP0 or AMP1) breaks the ADC-related code execution. I tried to enable amplifier with internal ADC clock/8 sync and start the conversion using ADSC bit in ADCSRA (as for B revision), via ADASCR in ADCSRB (as for A revision), and both. The loop
while (!(ADCSRA & (1<<ADIF))) ;
never exits. Removing the flag waiting leads to zero output from ADCH/ADCL registers. That is, no conversion was started.

What could be wrong? I have never seen such problems with other AVR devices but AT90PWM3 is a different one.

Could you provide a simple C code (or assembler) fragment which is a proven solution for AT90PWM3 device to start amplified ADC conversion?

Thanks in advance.
Oleg

Message added byEric Tinlot, 11.09.2006 13:11
Dear Mr Semyonov,

>1) How to identify the device revision (A or ?

Rev A is printed 90PWM3 and Rev B is printed 90PWM3B

>2) PSCnRB and PSCRV fuses.
Fuse works correctly, take care that under AVR studio a box checked means
programmed (it means logical 0).

for questions
3) BOD and Aref. and
4) Amplified ADC conversions.

I'll try to check it this week and give you a feed back.

Best Regards
Eric Tinlot
Atmel AVR Technical Support

--------------------------------
AVR support mail: http://support.atmel.no/
Atmel AVR page: http://www.atmel.com/products/avr/
Info and software: http://www.avrfreaks.net
Discussion forum: http://www.avrfreaks.net/phorum/
Distributors: http://www.atmel.com/dyn/general/contact.asp



> Hello!
>
> Having a self-made evaluation board with AT90PWM3, I have some issues I
> cannot understand. In fact, I think that those are problems with early chip
> revisions (my device was bought about half year ago).
>

Message added byOleg Semyonov, 12.09.2006 12:33
>>2) PSCnRB and PSCRV fuses.
>Fuse works correctly, take care that under AVR studio a box >checked means
>programmed (it means logical 0).

I use AVROSP software to flash/read fuses. They read as:

Reading fuse bits...
0xd7e2
0x1a

The extended fuse byte is 1A which means PSCxRB are programmed (0), and PSCRV is unprogrammed (1). Having this configuration, I observe low levels on PSC outputs during (~2 mV) and after (~7 mV) reset.

PS. I also use boot loader, so the rest of extended fuse byte is for 1Kbyte boot loader size and restart from boot loader.

Message added byGUILLET David, 04.10.2006 11:53
Little correction, it only works if ADC reference is set to AVCC, (BIT 6 (REFS0) of ADMUX set to 1. In any other case I observe jitting.


Message added byGUILLET David, 04.10.2006 11:45
Hello,

I'm using AT90PWM2 to make high frequency PWM (250Khz).

I observe jitting on the PWM if the external ADC ref is set to external, this jitting disappears if the reference is set to internal.

My external reference is perfectly clean (voltage reference IC) of 2.5V.

Do you have any suggestion to correct that ?

Best regards.

Message added byEric Tinlot, 06.10.2006 13:09
Dear Mr GUILLET

could you please confirm that AVCC and AREF pin are both decoupled to ground using small cerammic capacitor close to the chip ?


Best Regards

Eric Tinlot
Motor Control Customer Application Group
Atmel AVR Technical Support

--------------------------------
AVR support mail: http://support.atmel.no/
Atmel AVR page: http://www.atmel.com/products/avr/
Info and software: http://www.avrfreaks.net
Discussion forum: http://www.avrfreaks.net/phorum/
Distributors: http://www.atmel.com/dyn/general/contact.asp

Message added bydjdav@free.fr, 06.10.2006 13:27

Yes I confirm (they are soldered on the chip itself).

My further investigation shown that I had to use a 330uH / 100nF LPF to supply
AVCC. (in the datasheet, 10uH is advice, that's why I had) ... Then the jitting
is lowered to an acceptable value. Did you ever observe that ?

Best regards.



Selon avr@atmel.com:

> (Please keep the subject when replying to this mail)
>
> Dear Mr GUILLET
>
> could you please confirm that AVCC and AREF pin are both decoupled to ground
> using small cerammic capacitor close to the chip ?
>
>
> Best Regards
>
> Eric Tinlot
> Motor Control Customer Application Group
> Atmel AVR Technical Support
>
> --------------------------------
> AVR support mail: http://support.atmel.no/
> Atmel AVR page: http://www.atmel.com/products/avr/
> Info and software: http://www.avrfreaks.net
> Discussion forum: http://www.avrfreaks.net/phorum/
> Distributors: http://www.atmel.com/dyn/general/contact.asp
>
>
>

Setting the BOD fuses to have 4.3v BOD level (and 5v power supply), I have the following problem: setting via ADMUX Aref=AVcc leads to device reset. AREF pin is decoupled with external capacitor only.

А на питании какая блокировочная емкость, как далеко она от ног питания и насколько длинные дорожки от выходного электролита блока питания до блокировочного конденсатора по питанию? Я к тому, что не может ток зарядки емкости на ARef просаживать питание и вызывать честное срабатывание BOD?

На самом деле мне просто лень искать конкретную схему и вообще обсуждать это дело. Будет намного проще, если кто-то попрбует повторить названное и скажет - есть эффект или нет. Мне это интересно исключительно с точки зрения общего развития, но кому-то, может, поможет.

зажила PWMка . целый день потраттил.
с кривым программатором.
вообщем дальше лело времени.
работать с ней можно, соблюдая меры предосторожности.
будет правильны программатор, посмотрю чтос фузами PSC
пока же думаю применять меры предосторожности на стороне силы. автономно.

Поздравляю
А я только сегодня макетную плату заказал - небыло времени

1) How to identify the device revision (A or cool.gif?
My device is marked as:

90PWM3-16SQ
0540 04103AW

зажила PWMка . целый день потраттил.
с кривым программатором.
вообщем дальше лело времени.
работать с ней можно, соблюдая меры предосторожности.
будет правильны программатор, посмотрю чтос фузами PSC
пока же думаю применять меры предосторожности на стороне силы. автономно.

Согласно ответам из одной из веток точки опоры у вас ревизия "А". Согласно описанию такое определение действует на все кристаллы.