[SOLVED] N2+ 2x20 J1 header outputting correct Vout levels?

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tedzini
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[SOLVED] N2+ 2x20 J1 header outputting correct Vout levels?

Post by tedzini »

Shouldn't P2/P4 Vout = 5.0V? I'm getting 3.3V for both of them.
Shouldn't P1 Vout = 3.3V? Instead, I'm getting 0V.

I also tried a second N2+ and instead I measured:
P4=5.0V
P2=0.0V (again, shouldn't that be 5.0V?)
P1=0.0V (and, shouldn't this be 3.3V?)
(ground ref. on pin 9)

In either case, when I run gpio_status_n2.c the output indicates
P1 Vout = 3.3
P2 Vout = 5.0V
P4 Vout = 5.0V
P9 = GND
P14 = GND

Both of them were configured for UARTA/UARTB.

If this is in error, someone point me to the correct ref. & set up config.
I need to use one 3.3V line and one 5.0V line.

thanks,
-ted

crashoverride
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Re: N2+ 2x20 J1 header outputting correct Vout levels?

Post by crashoverride »

Most likely the wrong pins are being measured (upside-down). Note the location of "Pin 1" written on the N2 board (bottom left in the picture). If using a 40 pin cable, ensure its orientation also.
Image

The pin descriptions are shown below. Note this image is upside-down when viewing the connector on N2 from above.
Image

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mctom
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Re: N2+ 2x20 J1 header outputting correct Vout levels?

Post by mctom »

Yup, there's no way pins #2 and #4 could have different voltages, as both are physically tied together.

Also be super careful with these measurements, that's how most people break their SBCs.
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tedzini
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Re: N2+ 2x20 J1 header outputting correct Vout levels?

Post by tedzini »

Yep-- crashoverride,you were correct: ribbon cable "pin #1" was pin #2, etc., so carrier board terminals were connected to the wrong pins...
Issue resolved :-)

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