[time-nuts] Have I wrecked my FE-5680A?

[Nick Sayer]

I'm sending at most a single 9 byte command per second. I currently wait for the TX reg empty flag, which means I'm sending them all back-to-back. I'd have to instead wait for the TX complete flag and then add a delay after that. It's doable, but it would astonish me if 9 bytes in a row were causing it heartburn.

I'd love it if there were some way to restore the unit to factory settings / firmware. I'm on the cusp of sending an email to FEI to see if they do anything besides laugh at me. 

Sent from my iPhone

> On Apr 29, 2016, at 7:05 AM, Chuck Harris <cfharris at erols.com> wrote:
> 
> Likely what is happening is you are overrunning the RS232
> interrupt buffer, and that is causing a write into code
> space.  Odd that the firmware is changing, though.
> 
> Does this thing have Flash RAM, or battery backed NVRAM (Dallas)?
> 
> Oftentimes, NVRAM using devices use the NVRAM for both firmware,
> and data RAM space.  Things can get really ugly when that is done.
> 
> Also, to test my guess, put a delay between each character
> sent to the FE-5680A.  Say, 2 or 3 ms.
> 
> Needless to say before you do this, you need to develop a way
> of restoring the firmware.
> 
> -Chuck Harris
> 
> Bert Kehren via time-nuts wrote:
>> Sadly yes
>> The reason we have not released our GPSDO for the FE5690/50 and FE405 is
>> that we have experienced the same on all three devices. You are the 9th case
>> that I know of. We know very little as to what exactly causes it but we are
>>  incorporating circuitry to prevent it. What we know is that it is not a
>> particular code sequence on the RS232 port, but what happens the operating
>> code  is turning to mush. Some how the RS port is involved. Serious flaw on
>> all  FE devices since most likely the code was written by the same individual.
>> Bert Kehren
>> 
>> 
>> In a message dated 4/28/2016 9:02:28 P.M. Eastern Daylight Time,
>> time-nuts at febo.com writes:
>> 
>> Just as I  started testing the GPS discipline board prototype, my FE-5680A
>> seems to have  developed a very odd problem.
>> 
>> If I give it power, it outputs a “kinda”  10 MHz sine wave while it sweeps
>> around looking for a physics lock. This is as  expected.
>> 
>> About the time that I would expect the lock light to turn on,  instead the
>> output just stops. The lock light never comes on.
>> 
>> This  unit’s been working fine for months now. It’s conceivable that I’ve
>> sent it  some sort of serial command it couldn’t digest, but using the
>> Windows  calibrator software seems to work - albeit there not being any output
>> from the  oscillator at  all.
>> 
>> 
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