Searching \ for '[PIC] default configuration bits' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/microchip/devices.htm?key=pic
Search entire site for: 'default configuration bits'.

Exact match. Not showing close matches.
PICList Thread
'[PIC] default configuration bits'
2008\11\26@104812 by Artem Zezyulinskiy

flavicon
face
Hi, guys!

Do you think that chips that I buy from Microchip have default Config
Bits programmed?
If yes, how I can know what is the 'default'

--
Artem

2008\11\26@105928 by PAUL James

picon face

Read the datasheet.  AFAICR, all the default values are specified for
the various registers.


                                                       Regards,

                                                         Jim

-----Original Message-----
From: spam_OUTpiclist-bouncesTakeThisOuTspammit.edu [.....piclist-bouncesKILLspamspam@spam@mit.edu] On Behalf
Of Artem Zezyulinskiy
Sent: Wednesday, November 26, 2008 9:47 AM
To: Microcontroller discussion list - Public.
Subject: [PIC] default configuration bits

Hi, guys!

Do you think that chips that I buy from Microchip have default Config
Bits programmed?
If yes, how I can know what is the 'default'

--
Artem

2008\11\26@110420 by olin piclist

face picon face
Artem Zezyulinskiy wrote:
> Do you think that chips that I buy from Microchip have default Config
> Bits programmed?

Obviously something is in the bits.  They have to be either 0 or 1.  I think
they come from the factory in the erased state, which is 1.

> If yes, how I can know what is the 'default'

I can't think of a good need to expect the default to be anything in
particular.  Always specify all config bits in the source code.  Any decent
programmer can't rely on the PIC having come straight from manufacturing
versus having been programmed to arbitrary values, so once you program in
your firmware the original state becomes irrelevant.

If I really wanted to know I'd check the manaul, of course.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2008\11\26@110932 by Alan B. Pearce

face picon face
>Do you think that chips that I buy from Microchip have
>default Config Bits programmed?
>If yes, how I can know what is the 'default'

Whatever the datasheet says is the default for them. Typically this is the
erased state.

2008\11\26@110957 by Carl Denk

flavicon
face
I wouldn't assume anything, it's not that difficult to program the few
config bits. :)

Artem Zezyulinskiy wrote:
> Hi, guys!
>
> Do you think that chips that I buy from Microchip have default Config
> Bits programmed?
> If yes, how I can know what is the 'default'
>
>  

2008\11\26@113359 by alan smith

picon face
Yes they do.  Defaults are shown in the datasheets.  


--- On Wed, 11/26/08, Artem Zezyulinskiy <artemzezspamKILLspamsedatelec.com> wrote:

{Quote hidden}

> --

2008\11\27@032301 by Artem Zezyulinskiy

flavicon
face
Olin Lathrop a écrit :
> Obviously something is in the bits.  They have to be either 0 or 1.  I think
> they come from the factory in the erased state, which is 1.
>
>  
It's possible, but it don't specified clearly in the datasheet.

> I can't think of a good need to expect the default to be anything in
> particular.  Always specify all config bits in the source code.  Any decent
> programmer can't rely on the PIC having come straight from manufacturing
> versus having been programmed to arbitrary values, so once you program in
> your firmware the original state becomes irrelevant.
>  
I absolutely agree with you. I did it, but my subcontractor who
programme chips and populate the pcb do bad job. I receive the cards
with chips programmed on it, and 50% don't work. When I read the chip
through ICD2 I can see all the programme memory, but it not possible
because I specified the Code Protection Bit to ON. I suppose that the
Configurations Bits are not programmed.

> If I really wanted to know I'd check the manaul, of course.
>  
Be sure, I did it in the first place. But the default state of the
configurations bits is not specified.
This is a 16F946.
page 220 of the datasheet
http://ww1.microchip.com/downloads/en/DeviceDoc/41250F.pdf

Thank you all, for your responses. :)

2008\11\27@035203 by Wouter van Ooijen

face picon face
> Be sure, I did it in the first place. But the default state of the
> configurations bits is not specified.
> This is a 16F946.
> page 220 of the datasheet
> http://ww1.microchip.com/downloads/en/DeviceDoc/41250F.pdf

Top of that page:

"The Configuration bits can be programmed (read as
‘0’), or left unprogrammed (read as ‘1’) to select various
device configurations as shown in Register 16-1.
These bits are mapped in program memory location
2007h."

--

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu

2008\11\27@092744 by olin piclist

face picon face
Artem Zezyulinskiy wrote:
>> If I really wanted to know I'd check the manaul, of course.
>
> Be sure, I did it in the first place. But the default state of the
> configurations bits is not specified.

Then you didn't look very hard.  See page 25 of the programming spec,
DS41244E.  The defined bits are specified to default to 1 as expected.  The
single undefined bit always reads 1.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2008\11\27@100104 by Artem Zezyulinskiy

flavicon
face

> Then you didn't look very hard.  See page 25 of the programming spec,
> DS41244E.  The defined bits are specified to default to 1 as expected.  The
> single undefined bit always reads 1.
>  

Olin, do you think 1 - is factory programming value, or is value at POR
(see page 25 of the programming spec, DS41244E)?

Finally, I don't think that PIC come with a known state of Configuration
Bits.

Artem

2008\11\27@102424 by Wouter van Ooijen

face picon face
> Olin, do you think 1 - is factory programming value, or is value at POR
> (see page 25 of the programming spec, DS41244E)?

POR is not relevant: power cycling a PIC does not affect the state of
configuration bits (or other flash-stored bits). It is the 'after erase'
that is relevant.

> Finally, I don't think that PIC come with a known state of Configuration
> Bits.

Chips are sold in erased state.

--

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu

2008\11\27@114441 by Artem Zezyulinskiy

flavicon
face
Wouter van Ooijen a écrit :
>> Olin, do you think 1 - is factory programming value, or is value at POR
>> (see page 25 of the programming spec, DS41244E)?
>>    
>
> POR is not relevant: power cycling a PIC does not affect the state of
> configuration bits (or other flash-stored bits). It is the 'after erase'
> that is relevant.
>  
Exactly!

>> Finally, I don't think that PIC come with a known state of Configuration
>> Bits.
>>    
>
> Chips are sold in erased state.
>  
This is information that I need.

Thank you, Wouter.

Artem

2008\11\27@120247 by Wouter van Ooijen

face picon face
>>> Finally, I don't think that PIC come with a known state of Configuration
>>> Bits.
>>>    
>> Chips are sold in erased state.
>>  
> This is information that I need.

Actually, it isn't, it is what you asked for. Many famous stories exist
to illustrate that this is not the same :)

What you need to know is that a programmer nearly always does an erase
before starting the programming itself. Hence the state in which you get
the chip is not relevant.

--

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu

2008\11\27@124218 by olin piclist

face picon face
> Olin, do you think 1 - is factory programming value, or is value at
> POR (see page 25 of the programming spec, DS41244E)?

These are non-volatile bits, so Microchip can't specify the power on value
since it's whatever you last programmed it to.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

More... (looser matching)
- Last day of these posts
- In 2008 , 2009 only
- Today
- New search...