Posted by eeh March 16, 20052005-03-16
> You can put an AVR in a state where you cannot read out and verify
but you
> can still erase it.
How? I only know there are 3 kinds of lock bits. 1: Mode 2: Application Protection mode 3: Boot Loader Protection mode
Posted by R Adsett March 12, 20052005-03-12
In article <d0thij$jib$1@newsg2.svr.pol.co.uk>, ffffh.no.spam@hotmail-
spammers-paradise.com says...
> how _exactly_ did this: > > 1: "I was referring to SFC's post where he suggested searching for DES on > Atmel's website." > > help _you_ to understand this: > > 2: "Maybe he's thinking of this... > http://www.atmel.com/products/SecureAVR/Default.asp" >
Strangely enough it did provide enough extra information for it to make sense. This thread did start off on ISP code protection and the link made no sense (to me anyway) in that context but there was a branch off to Atmel providing DES support and that was enough extra information to bring the context back. Now someone who read those two responses without getting and remembering the branch could certainly be forgiven for being completly bamboozled at this point. And we've veered off topic well into the woods. <snip>
> In other words what part of "Maybe, he's thinking, Atmel, Secure, AVR" did > you not understand?
Mainly, what its relation to ISP was and what line of thought was being followed up.
>(Because, it really looks to me like you were just > making a point of the fact that the poster in question didn't quote - and if > you were making a point, why were you not honest about it and just say so, > rather than pretending to be baffled?).
Hey, just because you're baffled doesn't mean you can't make a point ;) I really wasn't following the line of thought though. Robert
Posted by Joe March 11, 20052005-03-11
how _exactly_ did this:

1: "I was referring to SFC's post where he suggested searching for DES on
Atmel's website."

help _you_ to understand this:

2: "Maybe he's thinking of this...
http://www.atmel.com/products/SecureAVR/Default.asp"

For me (and I'm going to make a wild assumption that it's the case for the
vast majority of people), it's plainly obvious what the context is in the
second example: i.e someone (It makes no difference to me who it was) was
referring to something to do with 'secure avr' on Atmel's website - a link
was provided for anyone that was interested.

In other words what part of "Maybe, he's thinking, Atmel, Secure, AVR" did
you not understand?  (Because, it really looks to me like you were just
making a point of the fact that the poster in question didn't quote - and if
you were making a point, why were you not honest about it and just say so,
rather than pretending to be baffled?).

What is it that I'm failing to see here?

Joe



"R Adsett" <radsett@junk.aeolusdevelopment.cm> wrote in message
news:VaSdnWVPyfDbhK_fRVn-vw@rogers.com...
> In article <N92dnc8ISKvVja_fRVn-oA@golden.net>, marycoy4@execyulinky.comy > says... > > "R Adsett" <radsett@junk.aeolusdevelopment.cm> wrote in message > > news:-aSdnW7QnfeNfazfRVn-iA@rogers.com... > > > In article <z6KdnUEOHo4VTazfRVn-pA@golden.net>,
marycoy4@execyulinky.comy
> > > says... > > >> Maybe he's thinking of this... > > >> > > >> http://www.atmel.com/products/SecureAVR/Default.asp > > > > > > Beg pardon? Context man, context. Who's thinking of it in respect to > > > what? > > > > > > I'm sorry for your confusion Robert. I was referring to SFC's post
where he
> > suggested searching for DES on Atmel's website. > > > > Thanks Mark, that makes a lot more sense. > > Robert
Posted by CBFalconer March 11, 20052005-03-11
mark thomas wrote:
> "R Adsett" <radsett@junk.aeolusdevelopment.cm> wrote in message >> marycoy4@execyulinky.comy says... > >>> Maybe he's thinking of this... >>> >>> http://www.atmel.com/products/SecureAVR/Default.asp >> >> Beg pardon? Context man, context. Who's thinking of it in >> respect to what? > > I'm sorry for your confusion Robert. I was referring to SFC's > post where he suggested searching for DES on Atmel's website.
You should realize that there is no reason that previous posts should be available at a given location, nor that they ever were there in the past. Thus quotations should include all the germane material, and excise everything that is not germane to a reply. An article should stand by itself. -- Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net) Available for consulting/temporary embedded and systems. <http://cbfalconer.home.att.net> USE worldnet address!
Posted by R Adsett March 11, 20052005-03-11
In article <N92dnc8ISKvVja_fRVn-oA@golden.net>, marycoy4@execyulinky.comy 
says...
> "R Adsett" <radsett@junk.aeolusdevelopment.cm> wrote in message > news:-aSdnW7QnfeNfazfRVn-iA@rogers.com... > > In article <z6KdnUEOHo4VTazfRVn-pA@golden.net>, marycoy4@execyulinky.comy > > says... > >> Maybe he's thinking of this... > >> > >> http://www.atmel.com/products/SecureAVR/Default.asp > > > > Beg pardon? Context man, context. Who's thinking of it in respect to > > what? > > > I'm sorry for your confusion Robert. I was referring to SFC's post where he > suggested searching for DES on Atmel's website. >
Thanks Mark, that makes a lot more sense. Robert
Posted by mark thomas March 11, 20052005-03-11
"R Adsett" <radsett@junk.aeolusdevelopment.cm> wrote in message 
news:-aSdnW7QnfeNfazfRVn-iA@rogers.com...
> In article <z6KdnUEOHo4VTazfRVn-pA@golden.net>, marycoy4@execyulinky.comy > says... >> Maybe he's thinking of this... >> >> http://www.atmel.com/products/SecureAVR/Default.asp > > Beg pardon? Context man, context. Who's thinking of it in respect to > what?
I'm sorry for your confusion Robert. I was referring to SFC's post where he suggested searching for DES on Atmel's website. -- MT To reply directly, please remove all 5 occurrences of the letter 'y' from my address.
Posted by David Powell March 11, 20052005-03-11
Hi,

Alot of the new Motorola ( freescale ) parts have code protection based
around the interrupt vector table in flash... so to unlock the CPU for
reading/writing you need to have the hex file of the previously loaded
firmware in that device. When the device programmer wants to unlock the CPU
it starts the programming cycle by sending the vector table down, if it
matches the table on the device, the device is unlocked.

Renesas CPUs allow you to set a 10 byte code when your ISP programming the
device, then the next time you want to access the device ( to read / write
flash ) you are required to send the 10byte code, much like the Motorola
method above.

Most of the ISP programmers I've seen do this for you automatically, in the
first case they ask for the previous hex file and in the second case it can
load the 10 byte unlock code manually or from a file.




"eeh" <eehobbyist@yahoo.com.hk> wrote in message
news:1110527595.935544.315770@o13g2000cwo.googlegroups.com...
> Hi, > > I know that many products support ROM upgrade or in system programming > (ISP). However, from my brain that logically to enable this feature the > mcu should not be locked. > > So I have a question that whether the above thinking is right ro not. > Or if it is right, is it possible to make ISP possible and > simultaneously protect our firmware code from being read during > verification? > > Thanks! >
Posted by R Adsett March 11, 20052005-03-11
In article <z6KdnUEOHo4VTazfRVn-pA@golden.net>, marycoy4@execyulinky.comy 
says...
> Maybe he's thinking of this... > > http://www.atmel.com/products/SecureAVR/Default.asp
Beg pardon? Context man, context. Who's thinking of it in respect to what? Robert
Posted by Ulf Samuelsson March 11, 20052005-03-11
> Depends on the micro. Often, ISP is locked out once you enable the > protection bits. Sometimes the verification process works by sending > the new data to the micro twice; first time to burn, second time to > verify. Sometimes you simply can't verify after setting the protection > bits, in which case the procedure is to erase the device, program code > memory, verify code memory, then program security bits. > > By definition, anyone who has the power to ISP-burn your micros has > enough information to copy them. >
You can put an AVR in a state where you cannot read out and verify but you can still erase it. Protection AND reprogrammability. You can also have a selfprogramming application where you send down a 3DES encrypted file which is decrupted and programmed into the flash. There is an application note available on that subject. -- Best Regards Ulf at atmel dot com These comments are intended to be my own opinion and they may, or may not be shared by my employer, Atmel Sweden.
Posted by mark thomas March 11, 20052005-03-11
Maybe he's thinking of this...

http://www.atmel.com/products/SecureAVR/Default.asp

--
MT