aazp
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RPi B+ test pads

Sat Oct 18, 2014 2:22 pm

As I have seen, B+ have numbers of test pads (PPx) but I can't find anything about them to use in troubleshooting. As I got RPi B+ suffers from lack of good documentation and technical information for users. :(

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mahjongg
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Re: RPi B+ test pads

Sat Oct 18, 2014 10:03 pm

Partial schematics are here, but true those do not list all the PP test points.
http://www.raspberrypi.org/documentatio ... matics.pdf


But i made such a list here it is, I hope it is of use:

PP1 5V from micro-USB
PP2 5V from micro-USB
PP3 GND
PP4 GND
PP5 GND
PP6 GND
PP7 5V after polyfuse
PP8 3V3
PP9 1V8
PP10 Goes from 3V3 to 2V on brownout
PP11 DAC_2V5 (for composite video DAC)
PP12 AUD_2V5 (for PWM audio drivers)
PP13 Goes from 3V3 to 2V on ACT activity
PP14 SD_CLK
PP15 SD_CMD
PP16 SD_DAT0
PP17 SD_DAT1
PP18 SD_DAT2
PP19 SD_DAT13
PP20 H5V
PP21 RUN signal (reset)
PP22 Goes from 3V3 to 2V on activity of green (link) ethernet jack LED
PP23 Goes from 3V3 to 2V on activity of yellow (speed) ethernet jack LED
PP24 COMPVID
PP25 AUDIO_L
PP26 AUDI_R
PP27 VBUS (USB 5V power)
PP28 ETH_CLK (25.000 MHz)
PP29 VC_TMS
PP30 VC_TRST_N
PP31 VC_CLK
PP32 VC_TDI
PP33 VC_TDO
PP34 GND
PP35 GPIO6 of LAN9514
PP36 GPIO7 of LAN9514
PP37 CAM_GPIO0
PP38 CAM_GPIO1
PP39 SCL0
PP40 SDA0

P.S. I do believe the list is accurate, but can't be 100% sure.

aazp
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Re: RPi B+ test pads

Sun Oct 19, 2014 4:42 am

Dear Mahjong, I don't have any voltage on the SD_CLK in my RPi when usd is inserted, and act led flashes 4 time, what's wrong?
and other SD pins are 3v3.

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mahjongg
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Re: RPi B+ test pads

Sun Oct 19, 2014 11:42 am

how do you measure that? You would need an oscilloscope to see the clock signal, as it only comes in burst during transfers.
https://en.wikipedia.org/wiki/Secure_Digital#Interface
SD_CLK is generated directly by the SoC using a GPIO port GPIO48, with only a 33 ohm ESD resistor (R25) in between.
ACT LED flashing in a regular pattern indicates an error status, ACT LED blinking in an irregular pattern indicates the driver is using the SD_CARD interface (including the clock signal) to (try to) read data from the card.

More info on ACT LED behavior in the boot problem sticky post.

p.s. what do you mean by "usd"?

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Burngate
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Re: RPi B+ test pads

Sun Oct 19, 2014 3:16 pm

mahjongg wrote:... p.s. what do you mean by "usd"?
micro-SD? (my keyboard hasn't got lower-case Greek either)

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rpdom
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Re: RPi B+ test pads

Sun Oct 19, 2014 3:47 pm

Burngate wrote:
mahjongg wrote:... p.s. what do you mean by "usd"?
micro-SD? (my keyboard hasn't got lower-case Greek either)
µSD? (Alt Gr + m on my keyboard) :)

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Burngate
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Re: RPi B+ test pads

Sun Oct 19, 2014 4:16 pm

Hmph.
How come when I try to be a smart-alec someone comes along and tops me?

aazp
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Re: RPi B+ test pads

Sun Oct 19, 2014 5:46 pm

usd means micro SD,yeah. :)
I checked the CLK with osciloscope ;)
And one more question : what about new NOOBS with no start.elf, what's the problem with 4 flashes of act led now? May the SOC and usd interface be corrupted? I bring up a boot problem here: http://www.raspberrypi.org/forums/viewt ... =89514&e=0

hayderOICO
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Re: RPi B+ test pads

Thu Feb 26, 2015 12:36 pm

Hello all!

I have a new Pi 2... are the PP test points still the same as the Pi B+ ?

I am asking because I want to solder some speaker output directly to PP25, PP26, PP6 (lack of space for the 3.5mm jack in the small enclosure... and would rather not fry my new Pi 2 :D

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DougieLawson
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Re: RPi B+ test pads

Thu Feb 26, 2015 12:44 pm

The B+ and 2B are mostly the same, except there's a lumping great 1GB RAM chip on the bottom of the 2B.
Microprocessor, Raspberry Pi & Arduino Hacker
Mainframe database troubleshooter
MQTT Evangelist
Twitter: @DougieLawson

2012-18: 1B*5, 2B*2, B+, A+, Z, ZW, 3Bs*3, 3B+

Any DMs sent on Twitter will be answered next month.

hayderOICO
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Re: RPi B+ test pads

Thu Feb 26, 2015 1:26 pm

well just soldered it up. everything seems ok. no sparks flying on bootup.

Anonymouses
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Re: RPi B+ test pads

Fri Apr 08, 2016 7:50 pm

What about for the pi 3

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