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Pi Zero test points

Posted: Sat Feb 25, 2017 8:34 am
by wayne.dolesman
I have tried to find a listing of the Pi Zero test points. I found threads like this viewtopic.php?p=874481#p874481 which talked about the B but the B test points do not entirely match the Zero (eg PP22, PP23, PP35, PP36, PP37, PP38, PP39, PP40).

So I did what I could to try to find them all, like pokemon!

Some of this is known but it seems like a good idea to have it all in one place. Feel free to post corrections/additions if I missed anything.

J5 (GPU) JTAG - 8 pin 0.5mm pitch FPC connector
1 - Reset - Pull low to reset the Pi
2 - TRST_N - pull low to reset the TAP
3 - TDI - Test data in
4 - Gnd - Signal ground
5 - TDO - Test data out
6 - TMS - Test mode select
7 - Gnd - Signal ground
8 - TCK - Test clock

Test Pads:
PP1 - Vcc - 5v
PP5 - Gnd - Ground
PP6 - Gnd - Ground
PP8 - 3.3v - Output of PAM2306AYPKE (U3)
PP9 - 1.8v - Output of PAM2306AYPKE (U3)
PP14 - SD CLK - SD card clock
PP15 - SD CMD -
PP16 - SD DAT0 -
PP17 - SD DAT1 -
PP18 - SD DAT2 -
PP19 - SD CD -
PP20 - H5V - HDMI 5 volt for EDID
PP22 - USB_DM - USB D- connected to host
PP23 - USB_DP - USB D+ connected to host
PP35 - Gnd - Ground
PP36 - Disconnected inside/right jumper beneath Q5 (this is connected in v1.2 hardware based on photo searches)
PP37 - HDMI SCL - I2C clock for DDC (for HDCP and EDID)
PP38 - HDMI SDA - I2C data for DDC (for HDCP and EDID)
PP39 - Pin 6 Q5 - I believe Q5 is an optically coupled isolator phototransistor (NA1C1 appears on Q5. NA1 is a transistor). I believe Pin 6 is the base.
PP40 - USB OTG ID - NC 3.3 ohm to gnd; OTG 0.3 ohm to gnd


I could not locate the outside/left jumper under Q5, it rabbits into the board and does not appear to pop its head back up to anything I could detect. The same goes for the unlabeled test point on the component side of the board next to the reset jumper (J2). This unlabeled test point does not appear on v1.2 hardware based on photo searches.

I took a wild guess with PP39, I could be incorrect about what Q5 is.

Re: Pi Zero test points

Posted: Wed Mar 22, 2017 12:24 am
by Witchy
Hi Wayne,

Your PP22 and PP23 are the wrong way round, PP22 should be D+ (green) and PP23 should be D- (white)

Cheers

W

Re: Pi Zero test points

Posted: Fri Mar 24, 2017 12:27 am
by wayne.dolesman
If that is the only error I made in that list then I am not doing too bad :)

Thanks

Re: Pi Zero test points

Posted: Fri Mar 24, 2017 1:19 am
by arraybytes
nice work, guess i will have do do the same for the W soon... I never thought of making a list for others... i guess i'm selfish. :(

Re: Pi Zero test points

Posted: Fri Mar 24, 2017 11:29 am
by Witchy
If that is the only error I made in that list then I am not doing too bad :)
Heh :) I've bookmarked the list, always handy to have around!

Cheers

W

Re: Pi Zero test points

Posted: Fri Apr 06, 2018 7:16 pm
by toldcodger
Thanks for the info.
Unfortunately the info proved the Zero was dead as the proverbial.

I tried to update it the other day and it was dead. I had been running it from a phone bank. I tested the output from the bank and it never went above 5.03 volts so i’m not sure what killed it. It worked the last time I used it.

When I tested the 3.3 v pp8 pad it came up with 0.1 volts
Pp9 was 2.3 volts instead of 1.8
And the winner was pp5 @ 10.2 volts.

I had already tried plugging it into a laptop USB port. It didn’t even beep never mind showing up in Device Manager.
So unless there’s a miracle worker online I think we can safely call this dead 🙁

But seriously, great work that info is very useful.

Re: Pi Zero test points

Posted: Mon Sep 17, 2018 7:43 pm
by offtherails2010
Thanks LOADS wayne.dolesman for making this List on the R-Pi Zero, extremely grateful from this Noob Beginner into this awesome Linux based world !

Major Thanks man - Keep up the awesome work !! :D

Re: Pi Zero test points

Posted: Tue Sep 18, 2018 6:29 pm
by PhilBr
When I tested the 3.3 v pp8 pad it came up with 0.1 volts
Pp9 was 2.3 volts instead of 1.8
And the winner was pp5 @ 10.2 volts
.

What were you measuring relative to? Where was the voltmeter negative connection? How was it powered at the time?
Phil