H8S2676 faulty chips

On Saturday, June 8, 2019 at 6:50:05 PM UTC-4, xym...@gmail.com wrote:
> Thanks.
> I'm told that we've been unable to determine where the chips were made.  Some people here are speculating that the chips were actually made by Renesas but were rejected during manufacture.  Does this seem believable?  
> 
> In a production run of 100 boards here, all boards failed.  We bought 6000 of these chips.  I find it hard to believe that Renesas would have as many as 6000 failures or that they would allow these chips to escape their factory.  The reason I'm interested is that if the chips were made by a non Renesas company, it's possible they have a solution and secondly, how did they get the design files?

Uhhh, design files?  They could have beach sand inside for all you know, right?  It is not uncommon for counterfeit chips to have totally bogus chips inside the package so they x-ray looking like something is in there.  

What happened with the company you bought them from?  Have they told you where they got them? 

-- 

  Rick C.

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On Sunday, June 9, 2019 at 3:43:17 PM UTC+12, Rick C wrote:
> On Saturday, June 8, 2019 at 6:50:05 PM UTC-4, xym...@gmail.com wrote:
> > Thanks.
> > I'm told that we've been unable to determine where the chips were made.  Some people here are speculating that the chips were actually made by Renesas but were rejected during manufacture.  Does this seem believable?  
> > 
> > In a production run of 100 boards here, all boards failed.  We bought 6000 of these chips.  I find it hard to believe that Renesas would have as many as 6000 failures or that they would allow these chips to escape their factory.  The reason I'm interested is that if the chips were made by a non Renesas company, it's possible they have a solution and secondly, how did they get the design files?
> 
> Uhhh, design files?  They could have beach sand inside for all you know, right?  It is not uncommon for counterfeit chips to have totally bogus chips inside the package so they x-ray looking like something is in there.  
> 
> What happened with the company you bought them from?  Have they told you where they got them? 
> 

Nope, they don't have beach sand.  They're functional to a point.  They were either made by Renesas or someone with the design files and the equipment to make them.  However I guess the chance that they were made by a legitimate manufacturer must be pretty slim as we wouldn't get 100% failure rate if they were legitimate.

xyman8@gmail.com writes:
> However I guess the chance that they were made by a legitimate
> manufacturer must be pretty slim as we wouldn't get 100% failure rate
> if they were legitimate.

Have you swapped a chip from an old, good board into one of your new
failing boards?  Did it work?

On Sunday, June 9, 2019 at 6:03:26 PM UTC+12, Paul Rubin wrote:
> xy...@gmail.com writes:
> > However I guess the chance that they were made by a legitimate
> > manufacturer must be pretty slim as we wouldn't get 100% failure rate
> > if they were legitimate.
> 
> Have you swapped a chip from an old, good board into one of your new
> failing boards?  Did it work?

I wasn't involved in the investigation but the guys who did it are fairly capable and they've established the new chips are only partially functional  - but I will check.

On Sunday, June 9, 2019 at 1:40:31 AM UTC-4, xym...@gmail.com wrote:
> On Sunday, June 9, 2019 at 3:43:17 PM UTC+12, Rick C wrote:
> > On Saturday, June 8, 2019 at 6:50:05 PM UTC-4, xym...@gmail.com wrote:
> > > Thanks.
> > > I'm told that we've been unable to determine where the chips were made.  Some people here are speculating that the chips were actually made by Renesas but were rejected during manufacture.  Does this seem believable?  
> > > 
> > > In a production run of 100 boards here, all boards failed.  We bought 6000 of these chips.  I find it hard to believe that Renesas would have as many as 6000 failures or that they would allow these chips to escape their factory.  The reason I'm interested is that if the chips were made by a non Renesas company, it's possible they have a solution and secondly, how did they get the design files?
> > 
> > Uhhh, design files?  They could have beach sand inside for all you know, right?  It is not uncommon for counterfeit chips to have totally bogus chips inside the package so they x-ray looking like something is in there.  
> > 
> > What happened with the company you bought them from?  Have they told you where they got them? 
> > 
> 
> Nope, they don't have beach sand.  They're functional to a point.  They were either made by Renesas or someone with the design files and the equipment to make them.  However I guess the chance that they were made by a legitimate manufacturer must be pretty slim as we wouldn't get 100% failure rate if they were legitimate.

What do they do right and what do they do wrong? 

If they are largely functional but are failing some small detail it is possible these are clone chips, a fresh design, not a literal duplicate of the original device.  

-- 

  Rick C.

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  + Tesla referral code - https://ts.la/richard11209

Rick C <gnuarm.deletethisbit@gmail.com> writes:
> If they are largely functional but are failing some small detail it is
> possible these are clone chips, a fresh design, not a literal
> duplicate of the original device.

It's weird: are you saying some illicit chipmaker did an unauthorized
redesign of this somewhat obscure and not exactly simple part, in order
to sell them under counterfeit labels, and left out functionality?  Does
that really happen?  Now that there is a market for working units of the
discontinued chip, could the illicit maker issue an erratum and spin
another run?  There is at least one possible customer...

On Sunday, June 9, 2019 at 3:53:58 PM UTC-4, Paul Rubin wrote:
> Rick C <gnuarm.deletethisbit@gmail.com> writes:
> > If they are largely functional but are failing some small detail it is
> > possible these are clone chips, a fresh design, not a literal
> > duplicate of the original device.
> 
> It's weird: are you saying some illicit chipmaker did an unauthorized
> redesign of this somewhat obscure and not exactly simple part, in order
> to sell them under counterfeit labels, and left out functionality?  Does
> that really happen?  Now that there is a market for working units of the
> discontinued chip, could the illicit maker issue an erratum and spin
> another run?  There is at least one possible customer...

You say "obscure", but no one makes low volume MCUs.  Most likely you are buying a chip that is not so obscure other than perhaps the combination of speed, package, temperature, etc that you chose.  Once they have made a die, they are going to sell it into each part number they can.  It might not even be a new chip design.  It's not impossible to reprogram the microcode on an existing chip to emulate another instruction set.  Then they only need to deal with the pin out issues.  

There was a serial port to USB converter chip that was cloned by reprogramming a different MCU chip.  It pretty much worked the same, but not quite.  The company making the original chip reverse engineered the clone enough to figure out how to reprogram it again, bricking the cable when used with their driver.  That didn't set well with Microsoft since they were distributing the driver with their software. 

I don't know what you have, but it sounds like you don't either.  I think you need more detail from your tech guys to figure out if you have a clone or a factory reject.  I would say turning a chip over to the factory would be useful, but they may not be interested in helping since they no longer make that chip. 

This is exactly why it's not a great idea to buy parts from third parties without some sort of testing and guarantee.  I was going to buy some EOL FPGAs that were at a good price at a reputable B list seller.  They said they had tested them and would guarantee the purchase price, but my assembly house said they wouldn't be responsible for the rework if they were faulty.  So I paid the higher price to get them from Arrow who still has stock more than five years after EOL. 

-- 

  Rick C.

  -- Get 1,000 miles of free Supercharging
  -- Tesla referral code - https://ts.la/richard11209

On 2019-06-09 Paul Rubin wrote in comp.arch.embedded:
> Rick C <gnuarm.deletethisbit@gmail.com> writes:
>> If they are largely functional but are failing some small detail it is
>> possible these are clone chips, a fresh design, not a literal
>> duplicate of the original device.
>
> It's weird: are you saying some illicit chipmaker did an unauthorized
> redesign of this somewhat obscure and not exactly simple part, in order
> to sell them under counterfeit labels, and left out functionality?  Does
> that really happen?  Now that there is a market for working units of the
> discontinued chip, could the illicit maker issue an erratum and spin
> another run?  There is at least one possible customer...

Maybe not even illicit or unauthorized (but you could probably check
that). I remember a case with an 68000 processor (I may have mentioned
that here before, but it seems apropriate in this topic)

We used a CPU card with a 68000 on it a long time ago. These boards were
in a rack, connecting to other cards via an 8-bit bus. This design was
in use for many years and boards were equiped with Motorola and TI
versions of the 68000 without issues. But then we created a new daughter 
card for the 8-bit bus. This card worked fine when a cpu card with a
Motorola 68000 was used, but failed when a TI 68000 was used.

I think that we can be pretty sure that the TI version was not
unauthorized, but I never did check. ;-)
So what made the TI versions fail?

I do not remember the exact details, but the cause was in 16-bit access
over the 8-bit bus, which depended on two consecutive accesses. The bus
control signals were derived from the 68000 bus signals by a PAL. In
this PAL, one of the 68000 signals was not included in the generation
of the 8-bit bus signals. But due to the timing of the other signals,
the timing of the bus signals was correct with the Motorola version of
the 68000. With the TI version however, a double access was generated
on both 8-bit halves of the 16-bit access, resulting in invalid
transfers.

After studying the datasheets, we concluded that both processors 
generated signals within specification. And the error was in our
generation of the 8-bit bus control signals. The design was probably
originally tested with the Motorola processor and afterwards only
a functional test was performed with the TI version. Which worked
because all cards at that time only used 8-bit access.

A simple change in the PAL code fixed this problem and then both
Motorola and TI 68000's worked as intended.

So what I am trying to say is that there is a possibility that your
new processors are in fact functioning correctly, but that an error
/omission in your board causes the difference in functionality.
Could be something as simple(?) as changed timing due to a new
manufacturing process. Something worth to check, in my opinion.


-- 
Stef    (remove caps, dashes and .invalid from e-mail address to reply by mail)

The lines are all busy (busied out, that is -- why let them in to begin with?).

Rick C <gnuarm.deletethisbit@gmail.com> wrote:
> You say "obscure", but no one makes low volume MCUs.  Most likely you are
> buying a chip that is not so obscure other than perhaps the combination of
> speed, package, temperature, etc that you chose.  Once they have made a
> die, they are going to sell it into each part number they can.  It might
> not even be a new chip design.  It's not impossible to reprogram the
> microcode on an existing chip to emulate another instruction set.  Then
> they only need to deal with the pin out issues.

I doubt this is a clone - I'd have thought this family was an unlikely
target for cloning (they don't seem high margin parts).

But you might be right in that it could be one part of the family remarked
as another.  For instance, MCU families like the Cypress PSoC are all the
same die internally, but with different features enabled by firmware.  An
unscrupulous supplier could remark the cheap chips as the expensive chips -
either without any changes (so you'd only notice if you try and use the
third UART, or whatever), or with hacked firmware to enable extra features.

But, as mentioned upthread, it would be worth checking whether there have
been any production changes to the genuine chip.  It could be the stock you
bought was a v1 chip while the manufacturer was selling v2 chips until EOL.
They might behave functionally the same, until you deviate slightly into
undefined behaviour that differs between the different versions.

Theo

The engineers here think the faulty chips were made by Renesas but rejected during manufacturing.  We found short a short term supply and we're going ahead with re-designing the board.  Thanks for all the comments.