EtherDue doesn't reliably start at POR

The EtherDue combines a super powerful 84MHz Cortex M3 with onboard ethernet connectivity. Dual Micro USB, a MicroSD card slot, switchmode power supply. 100% Arduino Due compatible. [Product Page]
chuckw
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EtherDue doesn't reliably start at POR

Post by chuckw » Tue Sep 16, 2014 10:24 pm

Hi,

I am finding that my EtherDue doesn't reliably start running its sketch after power is applied. This is true if I power it from USB or from the external power supply (I'm applying 9V). I've retreated to just running the "blink" example, which still shows the problem.

- adding a delay(50) as I've seen suggested (or even 500) to the beginning of setup() doesn't help.
- a regular Due starts reliably (same program)
- if power is removed for less than about 5 sec, the board will restart and run fine, but longer, no.

Any thoughts greatly appreciated.

- C

angusgr
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Re: EtherDue doesn't reliably start at POR

Post by angusgr » Wed Sep 17, 2014 4:58 am

Hi chuck,

Sorry to hear your EtherDue is misbehaving. I have a couple of questions that may help diagnose the problem.

- Do you have the USB cable connected to a computer when testing both power options? Is there a difference when the USB cable is disconnected and power applied via DC In?

- Do you have anything else connected to the serial UART pins digital 0 & 1?

- Does pressing the reset button always start the sketch reliably?


Angus

chuckw
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Re: EtherDue doesn't reliably start at POR

Post by chuckw » Wed Sep 17, 2014 12:43 pm

angusgr wrote:Hi chuck,

Sorry to hear your EtherDue is misbehaving. I have a couple of questions that may help diagnose the problem.

- Do you have the USB cable connected to a computer when testing both power options? Is there a difference when the USB cable is disconnected and power applied via DC In?

- Do you have anything else connected to the serial UART pins digital 0 & 1?

- Does pressing the reset button always start the sketch reliably?


Angus
- No difference whether USB cable powered or external 9V powered.
- The only difference I can make is time of power off: < 5 sec and it will restart, longer, no.
- Nothing connected to any serial pins.
- reset button reliably restarts it.

Comparing schematics, I see a 100 nF cap across the Reset pin to Vdd on EtherDue, vs a 10 nF on Due. Atmel suggests 10 nF in their manual. Perhaps there's some slight timing difference here?

chuckw
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Re: EtherDue doesn't reliably start at POR

Post by chuckw » Thu Sep 18, 2014 3:25 am

I'm considering replacing the 100 nF cap with a 10 nF, just a shot in the dark. Can someone tell me where it is?
Thanks,
- C

angusgr
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Re: EtherDue doesn't reliably start at POR

Post by angusgr » Fri Sep 19, 2014 4:50 am

Hi Chuck,

I can confirm this problem exists on at least some of our EtherDues.

Unfortunately the problem doesn't seem to be related to the reset pin deglitching capacitor. (Which is located just above the RESET button, slightly to the right, but replacing it hasn't made any difference for our affected board).

The Due is actually mis-starting up into the into bootloader mode from ROM. (You can confirm this by doing a "cold power on" connected to the Native USB port, the device enumerates as the atsam bootloader.)

This is only supposed to happen on reset if a certain value is read from a register in flash memory (GPNVM Bit 1). That value is not actually set, otherwise it would consistently power up to the bootloader, so the MCU must be glitching and reading the wrong value due to a transient problem.

We're going to keep investigating and we'll have a better answer for you soon. In the meantime if you want to arrange a return, please email support@freetronics.com.

Sorry for the inconvenience.


Angus

oldchap83
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Re: EtherDue doesn't reliably start at POR

Post by oldchap83 » Sun Sep 21, 2014 2:30 pm

Hello,
I have exactly the same problem.
I have 3 etherdue cards, I'll test the other two

--
Oldchap

angusgr
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Re: EtherDue doesn't reliably start at POR

Post by angusgr » Mon Sep 22, 2014 11:14 pm

Hi Chuck & Oldchap,

EtherDue v1.0 boards may be affected by the following bug: On power-on the board may start to the bootloader instead of running the onboard program, as if the ERASE button had been pressed. Pressing "reset" resumes normal operation.

The bug appears to be caused by undocumented behaviour in the ATSAM3X8E microcontroller regarding the "erase" input pin - according to the specification we shouldn't ever be seeing this.
The bug trigger is dependent on a second factor (normal internal variation of FET part U202). This is why we didn't pick it up in testing of preproduction prototypes (none of which exhibit the behaviour despite being identically specced).

A fix can be made by soldering a single surface mount resistor (0603 size) onto the board. We'll be publishing details of the fix in the next day or so for anyone who wants to apply it themselves. Alternatively people can return their boards to us and we'll repair them and send them back - please contact support@freetronics.com for details.

A v1.2 EtherDue revision with an integrated fix will be produced.

We've raised a support case with Atmel (makers of ATSAM3X8E) to let them know about the undocumented behaviour we're seeing. It seems the Arduino team may also be aware of the issue, as in the past 24 hours they've published a new Due reference design that independently shows the same fix we were testing.

Sorry for the inconvenience caused to anyone affected by this problem, this is a very unexpected and unfortunate combination of events.


Angus

angusgr
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Re: EtherDue doesn't reliably start at POR

Post by angusgr » Tue Sep 23, 2014 3:23 am

The repair guide is now online:
http://www.freetronics.com/pages/etherd ... wer-on-bug

Alternatively if you email support we'll arrange the return.

chuckw
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Re: EtherDue doesn't reliably start at POR

Post by chuckw » Tue Sep 23, 2014 4:59 pm

Excellent! Thanks for finding it. I'll try it out.
- C

chuckw
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Re: EtherDue doesn't reliably start at POR

Post by chuckw » Tue Sep 23, 2014 11:01 pm

The fix worked for me, for both the simple testcase and for my main code. I already had an 0805 resistor, and there was plenty of room for it.

Naked eyes may be adequate for young guys, by the way, but for those over 50, serious magnification is likely in order!

Thanks so much for your quick diagnosis of the problem!

- C

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