Dead Serial on Hummingboard?

[Ian Lepore]

On Thu, 2017-09-28 at 23:52 +0200, Bernd Walter wrote:
> On Thu, Sep 28, 2017 at 11:25:36AM -0700, Russell Haley wrote:
> > 
> > My son was playing on my computer yesterday and I found my
> > hummingboard on the floor this morning. It's not the first time
> > it's
> > hit the ground so I figured it was fine (lights are still on!).
> > 
> > I've tried to use the serial connection but it doesn't seem to be
> > transmitting my keyboard input. I can see the kernel output all the
> > way to login but it doesn't respond. ssh to the board works fine
> > through Ethernet, and the ftdi cable works fine on my BBB. I've
> > also
> > tried two different kernels (r324055M, r321601M).
> > 
> > There doesn't apear to be any physical damage (solder on the pins
> > looks okay) and I took the heatsink off and inspected the
> > processor.
> > It boots fine after I re-assembled, still no serial input.
> > 
> > Any  ideas? RIP hummingboard serial?
> Does it output on the serial?
> I'm not up to date with my iMX6 boards, but different boards used
> different
> iMX6 uarts for console port, so chances are that you are just on the
> wrong
> one.
> 

Afaik, all imx6 boards use uart0 for serial console except Boundary
Nitrogen series, which uses uart1.  In Russell's case, it was working
fine until the board was dropped on the floor, and then input stopped
working but output is still okay.

If it's not a problem with the input coming loose and being reconnected
to the wrong pin on the hummingboard header, then it's hard to imagine
what else the problem could be except a cracked solder joint from the
fall.  You might need a microscope (or at least a jeweler's loupe) to
see the damage.

-- Ian