hardware not found epidemic

Archiver

I teach a university level art/electronics class using the BS2. I'm a big
fan of the stamps, and it's definitely the easiest way to get a class of
mixed technical skills going on microcontrollers.

However, this quarter I've had an epidemic of stamps going bad. This
quarter, 7 of my 16 students have reported their stamps suddenly stopping
working with the classic "hardware not found" error. Parallax has been very
generous with sending the students who talk to them new stamps, but as you
can imagine this is still a very discouraging experience for the students.
This is vexing for me, because I haven't personally suffered from this
problem, and I haven't been able to pin down any specific causes of the
problem. We've been following standard input/output buffering precautions,
so I don't think that's the cause.

Anyway, I'm wondering the if anyone can address the following questions

1) Are there any general precautions that the first time stamp user should
follow to keep from damaging his/her stamp?
2) What is the leading cause of this issue?
3) Is it possible we got a bad batch? (all BOE kits bought at the same time)
4) Have other people suffered from this repeatedly?
5) How serious an issue is electrostatic discharge. Should everyone be
working on a grounded static mat?

Any ideas opinions on this subject welcome.

thanks,

Mark Allen

Archiver

At 10:58 AM 6/10/02 -0700, you wrote:
>I teach a university level art/electronics class using the BS2. I'm a big
>fan of the stamps, and it's definitely the easiest way to get a class of
>mixed technical skills going on microcontrollers.
>
>However, this quarter I've had an epidemic of stamps going bad. This
>quarter, 7 of my 16 students have reported their stamps suddenly stopping
>working with the classic "hardware not found" error. Parallax has been very
>generous with sending the students who talk to them new stamps, but as you
>can imagine this is still a very discouraging experience for the students.
>This is vexing for me, because I haven't personally suffered from this
>problem, and I haven't been able to pin down any specific causes of the
>problem. We've been following standard input/output buffering precautions,
>so I don't think that's the cause.
>
>Anyway, I'm wondering the if anyone can address the following questions
>
>1) Are there any general precautions that the first time stamp user should
>follow to keep from damaging his/her stamp?
>2) What is the leading cause of this issue?
>3) Is it possible we got a bad batch? (all BOE kits bought at the same time)
>4) Have other people suffered from this repeatedly?
>5) How serious an issue is electrostatic discharge. Should everyone be
>working on a grounded static mat?
>
>Any ideas opinions on this subject welcome.
>
>thanks,
>
>Mark Allen


I have experienced this error in noisy electrical environments and also when
trying to use a particular laptop computer that was not plugged into a wall
outlet. <--This was actually caused by a failing/bad parallel port on the
laptop. What type of setup do the students have? Is there one computer
for programming or are there several to choose from? Is this problem more
common on one computer vs. another or are all computers about the same? Do
you use the Parallel port extensively for other I/O demonstrations? i.e.
motor,
stepper control...etc. What kind of weather is in your area? (Dry/Humid)
Lightning?

Another thought:
Try forcing the ATN line HIGH or LOW during programming. On rare
occasion I have experienced problems trying to download a new program
into the BS2 when the previous program (still running) made use of
DEBUG
heavily.


Out of about 200 BS2's, I have only completely destroyed 2 BS2's due to static.

I have destroyed PIN's on BS2's due to poor EMF snubbing techniques.

---

Beau Schwabe Mask Designer IV - ATL
National Semiconductor Enterprise Networking Business Unit
500 Pinnacle Court, Suite 525 Wired Communications Division
Mail Stop GA1 Norcross, GA 30071

---

Archiver

>
>I have experienced this error in noisy electrical environments and also when
>trying to use a particular laptop computer that was not plugged into a wall
>outlet. <--This was actually caused by a failing/bad parallel port on the
>laptop. What type of setup do the students have? Is there one computer
>for programming or are there several to choose from?

multiple computers, all running off wall power. Defective stamps were
tested on multiple systems



>Another thought:
> Try forcing the ATN line HIGH or LOW during programming. On rare
> occasion I have experienced problems trying to download a new
> program
> into the BS2 when the previous program (still running) made use of
>DEBUG
> heavily.

How do you do that?, should I just connect atn to vdd via a resisitor?

Archiver

>
> multiple computers, all running off wall power. Defective stamps were
> tested on multiple systems
>
>
>
> >Another thought:
> > Try forcing the ATN line HIGH or LOW during programming. On rare
> > occasion I have experienced problems trying to download a new
> > program
> > into the BS2 when the previous program (still running) made use of
> >DEBUG
> > heavily.
>

Early on in my Stamping, I had a bsII treat me this way. What was
happening in my case was the program was running in a tight loop at the
start looking for an input to change states. With the program starting
with this loop, when interrupted by the atn line to start programming, it
evidently would start the program again before the programming sequence
could start, causing the HNF error. It would take 20 or more tries to get
another program loaded into the thing. The way I fixed it was to start the
program with a pause 500. I have never had another problem in the 4+ years
that I have been using them.

HTH,


--


Dale Harwood [noparse][[/noparse] N4VFF ]

internet> dale@h...

ax.25> n4vff@n4vff.#cha.tn.usa.noam

#include <std_disclaimer.h>