On Tue, 23 Jan 2018 19:09:51 +0000, RobH  declaimed the
following:

>On 23/01/18 18:53, Dennis Lee Bieber wrote:
>> On Tue, 23 Jan 2018 16:43:21 +0000, RobH  declaimed the
>> following:
>>
>>
>>> All of the above commands return 0
>>>
>>> I set the direction to IN then did gpio readall which shows the gpio17
>>> pin as IN and 0 voltage.
>>>
>>> Then I connected the positive jumper wire to the 3.3 volt pin, and then
>>> measured th voltage across the positive and ground wires, which was 3.28
>>> Volts.
>>
>>  If the sequence (below) always reports 0, then it would be safe to
>> presume that the GPIO circuitry is blown (or there is confusion as to which
>> pin is really being tested). I'm using the -1 option to specify the
>> physical header pin
>>
>> gpio -1 mode 11 in
>> #header 11 jumpered to GND (header pin 9, as I recall, is a ground)
>> gpio -1 read 11
>> #should be 0
>> #now jumper header 11 to 3.3V (header pin 1 or header pin 17)
>> gpio -1 read 11
>> #should be 1 -- if it is still 0, dead GPIO circuit
>>
>> #with nothing connected to header pin 11
>> gpio -1 mode 11 out
>> gpio -1 write 11 0
>> gpio -1 read 11
>> #should be 0
>> gpio -1 write 11 1
>> gpio -1 read 11
>> #should be 1, if this is 0 a REALLY dead GPIO, as the internal latches
>> can't hold an output value.
>>
>
>When I do
>
>pi@raspberrypi:~ $ gpio -1 mode 11 in
>pi@raspberrypi:~ $ gpio -1 read 11
>0
>pi@raspberrypi:~ $ gpio -1 read 11 Jumper header to 3.3v
>0
>gpio -1 read 11
>0
>
>Now nothing connected to the gpio pins
>
>pi@raspberrypi:~ $ gpio -1 mode 11 out
>pi@raspberrypi:~ $ gpio -1 write 11 0
>pi@raspberrypi:~ $ gpio read 11
>1

 Uhm -- the last command is missing the -1 option, which means you read
WiringPi GPIO 11, header pin 26, chip 7. If I understand the chart, that is
something like Clock Enable...

 The first sequence would indicate that the chip GPIO buffer/interface
to the board is dead... You didn't finish the second sequence (mode out,
write 0, read, write 1, read -- don't miss the -1 so the GPIO number is
correct for all.

 I did hook mine to a breadboard (3.3V, GND, and header 11 moved between
the two) to confirm the first sequence functioned as expected. At the
moment, I'm configuring the second SD card with newest NOOBS so unit will
be unavailable for some time (someday I need to update my BeagleBone Black
SD cards [first], and then flash the eMMC)
--
 Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

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