I would think BBB does not work because the oscillator is not running. check
for power suuplies . If you have a logic probe(O'scope would be better) check
oscillator output for frequency and amplitude close to its power supply. Also
check reset line(s) to be inactive, not in active reset .
From: John Syne <[email protected]>
To: [email protected]
Sent: Tuesday, October 11, 2016 12:13 PM
Subject: Re: [beagleboard] BegleBone Black stops oscillating and not make PORz
after power up
If the BBB oscillator is not running, then I suspect the processor is bad. If
you have two boards with the same issue, then I suspect the power supply you
are using is bad. One of the big issues with the BBB is it doesn’t like to
power down. Look at sheet 2 of the OSD335x schematics
http://octavosystems.com/octavosystems.com/wp-content/uploads/2016/05/OSD3358-SBC-Referece-Design.pdf
You will see some protection circuitry at the bottom center of the sheet. This
ensures the voltage difference between the 3v3 and 1v8 is never greater than
2V. The BBB does not have any such circuitry so when the 5V drops quickly, it
is possible for the 1v8 to drop quicker than the 3v3 and hence killing the
processor. This happened to me and I had to replace the processor.
The Beagleboard-x15 does have the same protection circuitry
(BeagleBoard-X15_RevA2.pdf sheet 4).
Regards,John
On Oct 11, 2016, at 7:05 AM, Николай Курочкин <[email protected]> wrote:
Two BeagleBone black boards with 1GHZ processors do not make boot sequece after
some unsucceseful attemts to format eMMC.It looks like they do not make PORz
sequence. Both ocillators inacvtive. NRESET_INOUT is low. PORZn input high. All
power voltages are OK.I use simple code wich make BBB to act as USB flash drive
to monitor eMMC with my PC. Code based on TI usb_dev_msc example in StarterWare.
It begin happens only with new boards. Old revision boards works OK.Any body
can help ?I going to use JTAG to debug this processors but not shure that JTAG
will work in this case.
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