Which GPIO pins are 0V at startup? - Raspberry Pi Q&A, Help & Troubleshooting

So I'm doing a project today with the Raspberry Pi 2 Model B and I realized that some (not all) of the GPIO pins output 3.3V at startup (I mean the data pins, not the power output pins). I cannot have it output 3.3V since I'm using the RPI to control a quadcopter and that would cause a mess if the motors ran at full speed at bootup. So do you guys know which pins are 0V (off) at startup and I can control using WiringPi?

Related

Serial cable problem sx56 to db9

Hi All,
I had reviewed the XDA connector wiring diagram, and confused about all the ground pins on sx56. I had order a standard stock serial cable from GOMATIC and it didn't work. Took it apart and rewired to the follow:
SX-56 pin 8 to db9 pin 3,
pin 10 to db9 pin 2
pin 2 to db9 pin 5. (gnd)
Still no go, should I be adding all the gnd pins to db 9 pin 5 gnd
( 5,16,17,18)
cheers,
edmond
Yep, you need all the ground pins shorted to device gnd.
I tryed shorting all the ground pins and my serial cable works fine for polling requirements.
Edmond
I converted my orginal O2 sync lead into a serial cable (seemed a cracking idea at the time).
took the connector apart, used the existing wires, cut the wires coming from the power socket and chucked a 9 pin d type on the other end. i left tx and rx straight so it could be connected easily to the cable (which is crossed) from my friends etrex gps, all works well.
I can't remember which ground i used but i just picked the easiest to re-route a wire to, if you are just doing 3 wire rs232 then you shouldn't need to short the grounds.

[Q] Nook HD/HD+ connector pinout and serial?

I see there was excellent work done by others to determine pinout for Nook Color/Tablet connector.
Now it would be great if we can get somebody to do the same for Nook HDs.
Additionally I really-really need a serial port out of the new Nooks for my kernel experiments (hopefully there's a serial in the big connector, but even if not, and somebody can help me to just solder wires somewhere on the pcb to gain serial, that would be great).
Please hit your hardware techie friends for me if you have any
If there is a serious person interested in this with no Nook to play, please contact me and I'll arrange for something.
(I already researched the Nook Color way of getting serial via twl on usb connector, but the newer twl in the newer Nooks does not have this car kit mode).
verygreen said:
I see there was excellent work done by others to determine pinout for Nook Color/Tablet connector.
Now it would be great if we can get somebody to do the same for Nook HDs.
Additionally I really-really need a serial port out of the new Nooks for my kernel experiments (hopefully there's a serial in the big connector, but even if not, and somebody can help me to just solder wires somewhere on the pcb to gain serial, that would be great).
Please hit your hardware techie friends for me if you have any
If there is a serious person interested in this with no Nook to play, please contact me and I'll arrange for something.
(I already researched the Nook Color way of getting serial via twl on usb connector, but the newer twl in the newer Nooks does not have this car kit mode).
Click to expand...
Click to collapse
I'm surprised no one has done this yet. I read somewhere that b&n simply modified an iPod connector and often times I've found that means they simply changed the order of the wires in order to gain propriety and therefore extra revenue. I have Two hd+ sitting on my desk with no charge because I'm too cheap to pay 30 bucks for a cable from b&n. I also have one charging cable cut in half so maybe I'll get on this myself, not that I can really take on another project at the moment.
The standard USB cable that came with the Nook only has 4 pins inside (going to the nook), so even if you cut your cable I don't think you will find anything useful.
I'm not sure about the HDMI one, it should have some extra pins inside to enable the video output, but I think that, without finding a compatible male plug with all the pins intact, it will be quite hard to find out the purpose of each pin.
Someone brave can do it on the nook side but I haven't open mine yet
Linux can use usb serial as console.
But I don't know is it possible to switch Nook usb subsystem to usb host early at boot.
lostnick said:
Linux can use usb serial as console.
But I don't know is it possible to switch Nook usb subsystem to usb host early at boot.
Click to expand...
Click to collapse
No, and by the time usb is up it's way too late in the booting game.
The big benefit of a real serial out is you get the output from bootloader and then transitioning into kernel including very early booting.
The nook end of the cable has only six pins. Two top and bottom on one side and one top and bottom on the other side. It would be easy to see what they connect to on the USB side. I'm definitely not an electronics engineer so I'm wondering if that is what is being discussed here and how that would do us any good? I would like to diy a car charger if I can.
pinout
I opened my Nook HD+, and there is a test point near the dock connector labeled usb-id. If this TP is shorted to GND with a slave USB device attached thru a USB-A to A gender bender, the Nook acts as host as expected per USB-OTG standard. This TP maps to pin 24. Unfortunately, this isn't one of the pins to a Nook HD+ USB cable.
The Nook HD+'s motherboard is labeled EXCELLENTLY. I've gotten most of the pins I can get easily. I think the remaining pins are for HDMI (which makes sense seeing B&N makes an HDMI adapter cable...). The HDMI adapter cable will probably get the remaining pins.
Here's the pinout I've got so far:
Pin - Signal
--------------------------------------
1 - USB VBUS (+5VDC)
2 - USB VBUS (+5VDC)
3 - HDMI 5V
4 - LINEOUT-DTC
5 - USB D-
6 - USB D+
7 -
8 -
9 -
10- GND
11-
12-
13- GND
14-
15-
16- GND
17-
18-
19- GND
20-
21-
22-
23-
24- USB-ID
25- LINE-L (Audio)
26- GND
27- LINE-R (Audio)
28- GND
29- GND
30- GND
---------- Post added at 06:27 AM ---------- Previous post was at 06:04 AM ----------
Also, there are two test points, SDA2-TX and SCL2-RX. These are I2C test points but I can't tell if they are the HDMI side or the system side. The HDMI chip is the TI TPD12s015, datasheet can be googled. Just a hunch that these are the HDMI side, since the datasheet says SDA_B and SCL_B are HDMI side, and they're labeled as SDA2 and SCL2.
connector type
Also, the Nook HD+ connector is NOT the same design as an Apple Dock Connector. The Apple connector has all the pins on one side of the internal fitting, while the Nook's connector has the pins on both sides.
So anyone attempting to mod their own connector should use a Nook connector.
Crud, i just bought one of those Samsung 30 pin to micro SD adapters hoping I could pull it apart and mod it, maybe I can't after all.
#edit# Is this our connector?
http://en.m.wikipedia.org/wiki/PDMI
Nope, not a PDMI...
myjess said:
Crud, i just bought one of those Samsung 30 pin to micro SD adapters hoping I could pull it apart and mod it, maybe I can't after all.
#edit# Is this our connector?
(link deleted, I'm too much of a noob to post links, I guess!)
Click to expand...
Click to collapse
No, from what I can tell, a PDMI connector is very similar to a Apple Dock Connector, with different pinouts assigned. The Nook HD+ has a unique connector layout from what I can tell.
It's similar to this:
...1...3...5...
...|...|...|...|...|...|...|...|...|...|...|...|..|...|...|
.+-v---v---v---v---v---v---v---v---v---v---v---v---v---v---v---+
.|
.+---^---^---^---^---^---^---^---^---^---^---^---^---^---^---^-+
.....|...|...|...|...|...|...|...|...|...|...|...|..|...|...|
.....2...4...6...
The Apple and Samsung have all pins on one side only, at double the density.
octachoron said:
Here's the pinout I've got so far:
Pin - Signal
--------------------------------------
...
Click to expand...
Click to collapse
Thanks!
Also, there are two test points, SDA2-TX and SCL2-RX. These are I2C test points but I can't tell if they are the HDMI side or the system side. The HDMI chip is the TI TPD12s015, datasheet can be googled. Just a hunch that these are the HDMI side, since the datasheet says SDA_B and SCL_B are HDMI side, and they're labeled as SDA2 and SCL2.
Click to expand...
Click to collapse
the TX one is the serial out, I got Adam Outler here at ABBQ to solder into it and I got the console out. Sadly it's not mapped anywhere in the connector, but at least I got my serial out now. We are less sure about the RX one, but I'll try it out once I get back home on Sunday.
Big thanks to Adam too!
TX & RX
verygreen said:
ThankDCCs!
the TX one is the serial out, I got Adam Outler here at ABBQ to solder into it and I got the console out. Sadly it's not mapped anywhere in the connector, but at least I got my serial out now. We are less sure about the RX one, but I'll try it out once I get back home on Sunday.
Big thanks to Adam too!
Click to expand...
Click to collapse
This is just a guess, but would not TX = transmit & RX = Recieve ?
Jimcisme said:
This is just a guess, but would not TX = transmit & RX = Recieve ?
Click to expand...
Click to collapse
Yes.
So TX definitely transmits the console output, we see it.
But tryign to input stuff onto RX pin does not result in anything visible, so that's why we are less sure if that's the input into the serial console.
But even if not, the console output is the more important one anyway for my kernel debugging plans.
Host Mode?
Does this imply that using the app to change USB to host mode will not work? I have seen several articles on using app with gender changer to get external keyboard or storage to HD+
I opened my Nook HD+, too. And I took some photos.
i40.tinypic.com/6yljxx.jpg
i40.tinypic.com/2yyrspi.jpg
Sorry, new user prevented from posting outside links in their messages.
Now I wonder if 5 test points of USB VBUS (+5VDC)、USB D-、USB D+、GND and USB-ID are connected to a MicroUSB Female adapter (5 pin) like most of Android smartphones and pads, will a MHL MicroUSB to HDMI cable work with the Nook HD+ ?
Has anyone ever opened up the HDMI adapter?
I would like to see whats inside before I rip mine open.
emottau said:
I'm surprised no one has done this yet. I read somewhere that b&n simply modified an iPod connector and often times I've found that means they simply changed the order of the wires in order to gain propriety and therefore extra revenue. I have Two hd+ sitting on my desk with no charge because I'm too cheap to pay 30 bucks for a cable from b&n. I also have one charging cable cut in half so maybe I'll get on this myself, not that I can really take on another project at the moment.
Click to expand...
Click to collapse
octachoron said:
I opened my Nook HD+, and there is a test point near the dock connector labeled usb-id. If this TP is shorted to GND with a slave USB device attached thru a USB-A to A gender bender, the Nook acts as host as expected per USB-OTG standard. This TP maps to pin 24. Unfortunately, this isn't one of the pins to a Nook HD+ USB cable.
The Nook HD+'s motherboard is labeled EXCELLENTLY. I've gotten most of the pins I can get easily. I think the remaining pins are for HDMI (which makes sense seeing B&N makes an HDMI adapter cable...). The HDMI adapter cable will probably get the remaining pins.
Here's the pinout I've got so far:
Pin - Signal
--------------------------------------
1 - USB VBUS (+5VDC)
2 - USB VBUS (+5VDC)
3 - HDMI 5V
4 - LINEOUT-DTC
5 - USB D-
6 - USB D+
7 -
8 -
9 -
10- GND
11-
12-
13- GND
14-
15-
16- GND
17-
18-
19- GND
20-
21-
22-
23-
24- USB-ID
25- LINE-L (Audio)
26- GND
27- LINE-R (Audio)
28- GND
29- GND
30- GND
---------- Post added at 06:27 AM ---------- Previous post was at 06:04 AM ----------
Also, there are two test points, SDA2-TX and SCL2-RX. These are I2C test points but I can't tell if they are the HDMI side or the system side. The HDMI chip is the TI TPD12s015, datasheet can be googled. Just a hunch that these are the HDMI side, since the datasheet says SDA_B and SCL_B are HDMI side, and they're labeled as SDA2 and SCL2.
Click to expand...
Click to collapse
Here is an updated pinout + PCB fragment with connector
Pin - Signal
--------------------------------------
1 - USB VBUS (+5VDC)
2 - USB VBUS (+5VDC)
3 - HDMI 5V
4 - LINEOUT-DTC
5 - USB D-
6 - USB D+
7 - GND
8 - GND
9 - HDMI CLK-
10- GND
11- HDMI CLK+
12- HDMI D0-
13- GND
14- HDMI D0+
15- HDMI D1-
16- GND
17- HDMI D1+
18- HDMI D2-
19- GND
20- HDMI D2+
21- GND
22- SDA2-TX(SCL2-RX?) - To be checked. Tx/Rx contact order according to HDMI connector pinout
23- SCL2-RX(SDA2-TX?)
24- USB-ID
25- LINE-L (Audio)
26- AGND
27- LINE-R (Audio)
28- AGND
29- GND
30- GND
As you can see, there is full HDMI signals set, so adaptor is just pass-through connection, no external chip needed in adaptor.
Regarding RX, it goes through TI TPD12s015. The PCB pad sits on chip output (system side), which is open-drain and can suppress this signal when HDMI 5V is not activated (reflecting connector's side not powered from HDMI 5V pullup). To activate it TPD12s015 input LS_OE and CT_CP_HPD must be set high (OMAP GPIOs) - VDAC-HDMI pad near processor?
But maybe CONS_2700_UART1 connector near processor will be more suitable for console?
the becalab
onlycash said:
Has anyone ever opened up the HDMI adapter?
I would like to see whats inside before I rip mine open.
Click to expand...
Click to collapse
Yes, that.
Have you done any ripping? I don't really have a use for the HDMI cable, but would buy and rip if I could get my mitts on the line level outputs. Can't imagine they'd plumb those, but I can dream.
Here is photos of my hdmi adapter(remove spaces from urls):
Code:
dropbox .com/s/f0tymbsva3cwwcb/hdmi1.JPG
dropbox .com/s/lpvubhb8at7lc8q/hdmi2.JPG
dropbox .com/s/pdw6ibn2zema04n/hdmi3.JPG
It is not so simple as i thought.
This is all very interesting, and some nice pics. I wonder, has anyone attempted (or even considered) to replace the annoying proprietary connector by soldering a replacement micro-USB onto the PCB? Is it even viable?
I can't understand why they would be so daft as to introduce a non-standard connection. Apple can just about get away with it because, well, they're Apple.

[Q] RPi GPIO ribbon pin numbers??

Hi! I've just built a Raspberry Pi Gameboy by with parts and instructions from Adafruit, with all the controls hooked up tp GPIO pins. I was wondering specifically if anyone knew what wire numbers on the gpio ribbon corresponded to what pins on the Model B's gpio. For example, would Wire #3 correspond to GPIO pin #6? Or something like that. I need this information to map the keyboard controls using Adafruit Retrogame, because wire numbers on the ribon don't seem to be the same as the GPIO numbers they're connected to. Any help would be appreciated!
Gameboy project: search Adafruit PiGrrl (Grrl is not a typo in this case) - First Result
GPIO ribbon: Go to adafruit . com / products / 862
I'm apparently not allowed to post links yet.
EDIT: Fbcp's framerate is so low because it screenshots the HDMI output and transfers it to the mini screen about every 25ms, giving about 28FPS. Any way I can change the delay?
Go to raspberry.org and look at the pin out for the gpio header.

[Q] Will a "data-only"-wired cable work on the D4?

Normal cables provide +5v on pin 1, for charging purposes. This also provides power to unused pin 4 for Factory Mode, if so wired.
I was wondering: will the phone connect to a PC without being supplied power at all (e.g. only Data +/- and GND connected), or is the 5v needed for sense purposes and/or to power the onboard USB controller?

GPS Signal not locking

I swapped my motherboard and now my gps does not lock. I tested the voltage and it measures 0.4 volts between the socket and ground. I have swapped the receiver still the same.
There are 2 pinouts on the board. When I removed the old wire there was a wire bridging the 2 pinouts, one wire to the gps unit connected across the 2 pinouts on the board. I was confused how this was, but assumed it was correct. The board is a kld2
I feel I have connected the wire incorrectly?

Categories

Resources