UART test point MeiG Smart SLM750 M2M module - Hardware Hacking General

I want to read out MeiG Smart SLM750 Module, is it possible to hook up UART TTL and get somehow into the system? EDL mode would probably also do it. The PCB has multiple layers, no schematic available. But there are plenty test points on it.
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Just download the Hardware Design Manual from https://en.meigsmart.com/productdetail/slm750-module.html.
I'm too lazy to make an account for that.
You can find the pins on the module then do a continuity check to find more convenient places on the main PCB.
The logic level in undoubtedly 1.8V
Make sure that you're using a USB UART that handles that (and not the more common 3.3V).
I did the same thing with the Quectel EC25-AF module in a Netgear LM1200.

SLM750 Module—MeiG—A Global Leading Supplier of Cellular Modules and Solutions
Have you researched these instructions?

ze7zez said:
Have you researched these instructions?
Click to expand...
Click to collapse
That's where I linked but you need an account to download.

Hm.. I don't have one but I have ordered 1.8V TTL. I checked all pins with DSO-138. I didn't see anything so probably device isn't powered.
edit: could not sign up. the register page does not take my chosen password.

alecxs said:
Hm.. I don't have one but I have ordered 1.8V TTL. I checked all pins with DSO-138. I didn't see anything so probably device isn't powered.
edit: could not sign up. the register page does not take my chosen password.
Click to expand...
Click to collapse
The password is 6-10 digits.
The web page is all screwed up:
Code:
Please enter your username Please enter 6-10 digit password
Please confirm your password Please enter your real name
Please enter your job title Please fill in the company name
Company website Please enter your phone number
Please enter the address Please enter your email account
Please fill in the verification code
Edit: Apparently they verify with SMS?
Your account has not been approved and you cannot log in temporarily
Click to expand...
Click to collapse

I think I figured test points based on the wiring colors. but device is completely dead so I don't see anything on oscilloscope.
any idea what the other two wires USB-DM and USB-DP are for?

alecxs said:
Any idea what the other two wires USB-DM and USB-DP are for?
Click to expand...
Click to collapse
USB 2.0 D+ and D-
They're the data lines.

I know but what are they intended for, connecting both the UART and USB signals to the same USB port, or different ports? Assuming the UART signals (DBG-RX and DBG-TX) operate at 1.8V logic level and the USB-DM and USB-DB signals operate at 3.3V-5V logic level, connecting the UART signals to the FT232RL and the USB data pins to the PC is maybe not the best approach. The FT232RL board provides not even pins for D-/D+ so should I solder it?

alecxs said:
I know but what are they intended for, connecting both the UART and USB signals to the same USB port, or different ports?
Click to expand...
Click to collapse
They are unrelated except for sharing the same connector.
If this is going to be peripheral then there really should be an input for 5V labelled "Vbus".
Of course they could be playing fast and loose with the USB 2.0 standard too.
If this is going to be host then you'll need to supply +5V for the peripheral.

would be great to have usb so I could try edl. but there is no Vbus, only the usb data lines. there is one 5 V voltage on another connector (first) but that is power for the display. If I translated right, the pin 19 (third connector) is for boot mode.

The first test is to put a DVM on DP vs Gnd. See ~3V, it's waiting for a USB 2.0 full/high speed connection.
DVM on DM vs Gnd. See ~3V, it's waiting for a USB 2.0 low speed connection.
No ~3V anywhere? Then it's waiting to see 5V on Vbus or else the USB is just disabled.
(I've even made up a little adapter to check this with a couple of LEDs.)
If you see ~3V on DP, make yourself a 3 wire USB cable.
White = DM, Green = DP, Black = Gnd, Red gets insulated and not connected.
"Boot mode" is normally a GPIO input for EDL mode that is asserted with 1.8V
But don't just plow that voltage in! Use a nice resistor of 1k ohm or so in series.
Don't use a voltage higher than 1.8V! If you have a fresh 1.5V AA or AAA battery that should give you 1.6V, which is plenty.
Of course, you need to do a reset at the same time.

on the UART there is 7 mV an 16 mV, on the USB there is nothing.

alecxs said:
on the UART there is 7 mV an 16 mV, on the USB there is nothing.
Click to expand...
Click to collapse
You sure that it's powered up?
Many (some?) of these things have two different UARTs.
If there is a Vbus connection that's not getting its 5V that may be the problem.
You need a real pinout of the module.
I never got an SMS back (but I forgot to put a +1 on my phone number).

the board is powered by 3.7 V battery and 25-42 V DC input (I don't have atm) for DC converter I tested with 12 V battery. not sure it is on at all. if there is a Vbus it must be self-powered as there is no pin for on the connector.

alecxs said:
the board is powered by 3.7 V battery and 25-42 V DC input (I don't have atm) for DC converter I tested with 12 V battery. not sure it is on at all. if there is a Vbus it must be self-powered as there is no pin for on the connector.
Click to expand...
Click to collapse
Oh, you mean it's Ethernet POE? Bring it over here. I have a 12V to 24V converter I use for my PtoMP microwave that uses POE.
Or I'd use my current sensing power supply to battery substitute to watch it boot up that way.
Are you sure the battery has any charge?
Also, between the module and the GPS antenna it looks like there was a power connector that ripped off?
Or are my eyes deceiving me?

Hehe I could send you one, but I am afraid the shipping from germany would take ages. The ripped off connector is for the piezo speaker, the battery connector is on the back site of the board, along with the main connector. Battery is charged and I can measure 3.9 V on the test point, but maybe needs additional wires to get powered.
I have also the pinout for the rest of the connector (see github of the picture in OP)
The next days I will connect it to its origin power source 36 V battery with full pinout and check again.
I am curious it is a android device I can maybe get a dump of the app data. it should not have any security as it is intended to boot up on mobile data without any user input. But it's not important to me, just for fun.

alecxs said:
I am curious it is a android device I can maybe get a dump of the app data.
Click to expand...
Click to collapse
I wouldn't think that it is Android, but Android-ish.
I've run into this before with things using Android abl and Android image format but certainly not Android subsystem!
Is the 3.7V battery full size or backup size?
Many (some?) of these devices use NAND instead of eMMC and they are designed to have power disconnected without warning.
Do you have a bunch of these?
Also, your device has a squirrely jumper around a regulator (directly above GPS antenna).
Are they all like this?

there exist different revisions of that board, 95% identical, but all have these unused antenna connectors on it. I can't see any jumpers, that are spring contacts for more antennas in the cover. I don't know if there is any eMMC it's all under the hood.
the battery is only backup for GPS and GSM.

So I shorted the reed sensor and now on the oscilloscope I can definitely see 1.8 V transmission (on the yellow pin) but nothing on usb. will try to connect to PC and see what happens.

Related

Will a Hermes Car Charger work on the Kaiser?

I remember reading in a review long time ago that it wouldn't work. Just wanted to confirm this. Thanks.
All Hermes Chargers and Headset Adapters work fine, some cradles work OK too but the fit isn't perfect.
RemE said:
All Hermes Chargers and Headset Adapters work fine, some cradles work OK too but the fit isn't perfect.
Click to expand...
Click to collapse
Thanks for the info!
what about the batteries from the hermes ?
Woah I forgot all about this thread.
That free HTC car charger that AT&T sent for the 8525 didn't work on the Tilt.
ZzFDKzZ said:
Woah I forgot all about this thread.
That free HTC car charger that AT&T sent for the 8525 didn't work on the Tilt.
Click to expand...
Click to collapse
It worked fine on mine.
new_ppc_user said:
what about the batteries from the hermes ?
Click to expand...
Click to collapse
Nope, they won't fit.
ZzFDKzZ said:
I remember reading in a review long time ago that it wouldn't work. Just wanted to confirm this. Thanks.
Click to expand...
Click to collapse
Any Mini-Usb charger should work on the Tilt or any other device with a Mini-Usb port. I have used my Razr's on my Tilt and Hermes and on a sony and a nokia.
I think we need to settle this once and for all.
Source: http://wiki.xda-developers.com/index.php?pagename=ExtUSB
The Kaiser ExtUSB Connector...
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As we see the USB Connectors are on the Top and the "specialized audio connectors" on the bottom. Notice Pin 1 is Power, No other are power.
Now lets look at Mini-USB Series B, the standard USB connector on these Chargers.
Source: http://www.accesscomms.com.au/reference/USB.htm
Notice When you hold the Mini-USB Type B Connector with the Shorter part down that Pin 1 is to the far right. Pin 1 is also Power.
Code:
Mini-USB Type-B Pinout & Cable Color Code
Pin Wire Color Function
1 Red V BUS (5V)
2 White D-
3 Green D+
4 Not connected ID
5 Black Ground
Now we look at the ExtUSB diagram notice the bezel near the end with Pin 5. Notice Pin 1, which we know is Power, is to the "left." It matches up perfectly with Pin 1 Power on the USB Connector.
Also notice on Mini-USB Type B that there is no Pins on the Bottom to interfere with The Extra Pins on the HTC ExtUSB port.
So as long as the charger only provides power on Pin 1, which any good charger will, it will work with the Kaiser.
wikipedia's USB Article said:
The USB specification provides a 5 V (volts) supply on a single wire from which connected USB devices may draw power. The specification provides for no more than 5.25 V and no less than 4.75 V (5 V±5%) between the positive and negative bus power lines. Initially, a device is only allowed to draw 100 mA. It may request more current from the upstream device in units of 2 mA up to a maximum of 500 mA.
[...]
On-The-Go and Battery Charging Specification both add new powering modes to the USB specification. The latter specification allows USB devices to draw up to 1.5 A from hubs and hosts that follow the Battery Charging Specification.
Click to expand...
Click to collapse
So If the Charger Provides up to 1.5A via Pin 1, it should work.
*Caveat: I don't know for certain that the HTC Kaiser draws 1.5A, but I'm sure it does. Hypothetically, on a USB bus the Bus will not provide more power than the Device Actively draws. So if for some obtuse reason HTC went against all Smart Design and Engineering, and created a Device with a Mini-USB Type B connector that couldn't handle 1.5A. A charging only charger that feeds it 1.5A it may blow it out.
I could not find any information on this. If someone knows or has a data sheet that says the HTC Kaiser can draw up to 1.5A then any charger that doesn't provide more then 1.5A will work fine. Any decent Charger maker would know that USB devices cannot handle more then 1.5A. Thusly not providing more then 1.5A on a charging-only charger.
JimmyMcGee said:
I think we need to settle this once and for all.
Source: http://wiki.xda-developers.com/index.php?pagename=ExtUSB
The Kaiser ExtUSB Connector...
[/I]
Click to expand...
Click to collapse
Well said.
JimmyMcGee said:
I think we need to settle this once and for all.
Source: http://wiki.xda-developers.com/index.php?pagename=ExtUSB
The Kaiser ExtUSB Connector...
As we see the USB Connectors are on the Top and the "specialized audio connectors" on the bottom. Notice Pin 1 is Power, No other are power.
Now lets look at Mini-USB Series B, the standard USB connector on these Chargers.
Source: http://www.accesscomms.com.au/refer...5 came with does not work with the AT&T Tilt.
Click to expand...
Click to collapse

How to make your own Motorola "Factory Cable"

Over in this post Cellzealot opined that I might be willing to share the pinout of the "factory cable" clone that I worked up. I absolutely am, but needed to find several hours of free time to do the writeup, images, etc.
The other night I set aside the time and did the writeup. If you would like to make your own cable, you can read the writeup here.
To oversimplify it, here is the map:
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The map is simple enough. The main problem (as detailed in the writeup I linked to above) is that since pin 4 is normally unused in a Mini/Micro B connector, there is no wire connected to it (to tie to), and in the case of the Mini B that I surgically dissected, the actual pin for pin 4 was nipped off at the back of the connector as well.
This doesn't preclude you from making a cable as you can always order brand new connectors and solder them up any way you like.
I'll be happy to answer any questions you might have in this topic.
great guide
Thanks for linking this to us! This would be tremendously useful to many on this forum. My question is, since the docks Motorola sells basically do the same thing, could the process be applied like callen81 did to make USB host functionality? It seems like the same process is used, albeit simpler.
Or just buy a USB 3.0 cable!
ya i picked up like three for like 1.50 each. monoprice.com has alot of cables for super cheap, good quality too
edit, i also got the 10 footers so i dont have to be bounded to the 4 footer that comes with it
Moved to proper forum.
Guys, a factory cable is not like the micro USB cables you buy, nor the standard "OTG" micro usb cables/adapters to become USB host.
Notice that PIN4 is tied to POWER, the +5V on PIN1, not to ground on PIN5 as in OTG cables (or left floating like on most mini/micro cables.)
This cable is essentially for being able to nvflash the phone, although perhaps it has other uses I am unaware of.
eval- said:
Guys, a factory cable is not like the micro USB cables you buy, nor the standard "OTG" micro usb cables/adapters to become USB host.
Notice that PIN4 is tied to POWER, the +5V on PIN1, not to ground on PIN5 as in OTG cables (or left floating like on most mini/micro cables.)
This cable is essentially for being able to nvflash the phone, although perhaps it has other uses I am unaware of.
Click to expand...
Click to collapse
It can also be used to charge the phone while flashing SBF.
Sent from my MB860 using XDA App
eval- said:
Guys, a factory cable is not like the micro USB cables you buy, nor the standard "OTG" micro usb cables/adapters to become USB host.
Notice that PIN4 is tied to POWER, the +5V on PIN1, not to ground on PIN5 as in OTG cables (or left floating like on most mini/micro cables.)
This cable is essentially for being able to nvflash the phone, although perhaps it has other uses I am unaware of.
Click to expand...
Click to collapse
isn't it also possible to use a usb keyboard with this method given that you have a usb powering hub in the middle?
The most useful thing to do at this point would be linking places that sell easily modified cables / adapters. As he said 99% of cables you find will not have the 5th wire connected or soldered on to the connector. Even if I had a cable or source of cables that had an easily solderable 5th pin this cable would be decently cheap to make. Most of the space cables I've hacked apart just have 4 solder points and a 'dummy' pin #4 (what, to look cool?) sigh.
bearsfan172 said:
It can also be used to charge the phone while flashing SBF.
Click to expand...
Click to collapse
I can't say for the Atrix, but for every other phone I've used the cable on, while it will power the phone while flashing, it will not charge the phone while flashing.
eval- said:
Guys, a factory cable is not like the micro USB cables you buy, nor the standard "OTG" micro usb cables/adapters to become USB host.
Notice that PIN4 is tied to POWER, the +5V on PIN1, not to ground on PIN5 as in OTG cables (or left floating like on most mini/micro cables.)
They do indeed have many uses
This cable is essentially for being able to nvflash the phone, although perhaps it has other uses I am unaware of.
Click to expand...
Click to collapse
They do indeed have many other uses besides the nvflash interface which is strictly for Tegra based devices. They not only power the device without battery, but autoload the Motorola networking driver and other interfaces for diagnostic mode NV access with both Motorola and Qualcomm service ware as well as flash tools like RSD Lite.
The device is always initialized properly and identified by the applications for various operations.
Similar powered cables have been used for all P2K generation Motorola devices for many years in various configurations. The real factory cables are made with a Mini USB B end and come with an adapter so they are compatible across a much wider range of older devices.
We hope very much that getting this info out will generate a lot of outflow for the many ways to apply the unique properties of these cables for newer devices.
In another topic Kholk had an idea that does away with the "missing pin 4 on the micro" problem. You can sacrifice a Motorola Mini-to-Micro USB adapter (SKN6252) which is wired for all 5 pins. This makes it a heck of a lot easier for the average Joe to make one and avoid the expense of buying a custom-made cable.
For most folks that would try this, that tip is all they need to proceed. If you want more detail, I did a step by step here.
If you make one up, post up and let me know how it went.
Enjoy!
MotoCache1 said:
In another topic Kholk had an idea that does away with the "missing pin 4 on the micro" problem. You can sacrifice a Motorola Mini-to-Micro USB adapter (SKN6252) which is wired for all 5 pins. This makes it a heck of a lot easier for the average Joe to make one and avoid the expense of buying a custom-made cable.
For most folks that would try this, that tip is all they need to proceed. If you want more detail, I did a step by step here.
If you make one up, post up and let me know how it went.
Enjoy!
Click to expand...
Click to collapse
I'm working on making my own, just to see if it'll work. I think it's going to turn out more frankenstein-y than yours, however.
PixoNova said:
I'm working on making my own, just to see if it'll work. I think it's going to turn out more frankenstein-y than yours, however.
Click to expand...
Click to collapse
Cool. I'd love to see it when you're done (if you wouldn't mind posting a pic). As long as you get the pinout right, it will work. Your attempt can't possibly be worse than my initial prototype was. If you have an SKN6252 lying around, you could actually make a pretty respectable looking cable.
Where can you buy one of these if your not good at soldering??
Make a friend who is good at soldering.
Does anyone know why Moto is allowed to call their connector USB when they don't comply to USB.ORG's standards and do things their own way?
cellzealot said:
They do indeed have many other uses besides the nvflash interface which is strictly for Tegra based devices. They not only power the device without battery, but autoload the Motorola networking driver and other interfaces for diagnostic mode NV access with both Motorola and Qualcomm service ware as well as flash tools like RSD Lite.
The device is always initialized properly and identified by the applications for various operations.
Similar powered cables have been used for all P2K generation Motorola devices for many years in various configurations. The real factory cables are made with a Mini USB B end and come with an adapter so they are compatible across a much wider range of older devices.
We hope very much that getting this info out will generate a lot of outflow for the many ways to apply the unique properties of these cables for newer devices.
Click to expand...
Click to collapse
Moto has been using nonstandard USB cables since they came out, many of which were dumb devices. The reasoning that they needed to be different so that they can do X Y or Z is bull. They want to lock you into Moto cables. No one has ever shown a logical reason for being different. You can flash phones with regular USB cables so the logic for a different format holds no validity.
Does this mean we could make one of these cables and have the phone "think" its either docked in the car or in the HD dock? I assume for the HD dock you might need added power but why cant I make a USB cable, plug it into my phone and hook up a USB hub to it like the dock?
not to hi-jack but it would be interesting to see if anyone has made their own docks, somehow the 3.5mm audio is integrated into the dock and is played through the usb cable...
Using the factory cable, Not insert the battery, display SVF: 105:1:2
Failed to boot 0x1000, infinite reboot

USB cord power supply

Hello there,
I would like to know if any one had seen or used this cable :
http:\\www.witglobal.com/goods-4595-USB+Ch...00+*USB+Charger+Cord+Cable-Free+Shipping.html
I found the idea very interesting , what do you think about it please ?
By the way some ones on the net said this is a fake seller, any idéal?
Thanks
Well, the cable could very well exist, but it will not work.
As they write
We only guarantee this USB charger cable works when you connect with a 12V output USB port
Click to expand...
Click to collapse
and USB is by the standard providing 5V...
eppeP said:
Well, the cable could very well exist, but it will not work.
As they write
and USB is by the standard providing 5V...
Click to expand...
Click to collapse
ok, thanks for this information.
eppeP said:
Well, the cable could very well exist, but it will not work.
As they write
and USB is by the standard providing 5V...
Click to expand...
Click to collapse
is usb 3.0 even 12 volt???
samaliset said:
By the way some ones on the net said this is a fake seller, any idéal?
Thanks
Click to expand...
Click to collapse
Considering their claims, I'd hardly call them legit... Seriously.. "Requires a 12v USB port?" There's no such animal...
Besides which, even if you COULD pump 12v down the USB cable to the A500, all you'll manage to do is either a) nothing at all, or b) fry your A500.
FloatingFatMan said:
Considering their claims, I'd hardly call them legit... Seriously.. "Requires a 12v USB port?" There's no such animal...
Besides which, even if you COULD pump 12v down the USB cable to the A500, all you'll manage to do is either a) nothing at all, or b) fry your A500.
Click to expand...
Click to collapse
Floating correct me if I'm wrong but i don't understand how you can just say it wont work or fry your a500 if there's 12v and 1.5A then how would it not work???
once again correct me if im wrong
gears177 said:
Floating correct me if I'm wrong but i don't understand how you can just say it wont work or fry your a500 if there's 12v and 1.5A then how would it not work???
once again correct me if im wrong
Click to expand...
Click to collapse
Because the USB port on the A500 is NOT designed to take a 12v input. It's only way of charging is through the dedicated 12v power connector. What do you think happens when you push voltage down something not designed for it?
FloatingFatMan said:
Because the USB port on the A500 is NOT designed to take a 12v input. It's only way of charging is through the dedicated 12v power connector. What do you think happens when you push voltage down something not designed for it?
Click to expand...
Click to collapse
You can't connect it that way.
USB Type A Male to DC Power Plug Connector For ACER ICONIA TAB A500 TABLET
Click to expand...
Click to collapse
And my previous answer still stands.
Ah, I didn't spot one end was a regular power connector. Still, it's not gonna work anyway. Even car USB adapters step the voltage down to 5v.
FloatingFatMan said:
Ah, I didn't spot one end was a regular power connector. Still, it's not gonna work anyway. Even car USB adapters step the voltage down to 5v.
Click to expand...
Click to collapse
ive charged my iconia off a car before -_- should work unless this actually steps voltage up
http://www.amazon.com/DBTech-Portab...=UTF8&qid=1339650670&sr=8-1&keywords=car+plug
Not exact one but like it sorry...
I would be highly suspect. Stepping DC voltage up is not a simple task...only way I know of would be to convert to AC run through a transformer then a rectifier to convert back to DC. If this comes with a 12v power supply with a USB header I would not even allow it in my house, at some point someone will plug a phone into it and fry it.
The power inverter for the car also specifically puts 5v and 500ma (2.5 watts which is waaay less than the 18 watts the tablet is designed to draw at max).
Most USB ports are 500 ma....some are 1 amp but still less than 33% what the a500 needs.
I'd be very suspicious of this.
Sent from my A500 using XDA
Save your money and time. It is legit item which unfortunately, doesn't work. At all.
Anyone else considering this purchase will hopefully see my post and save his/herself the $ and pass it by. As it wasn't an expensive experiment, I did purchase one. I figured it might be worth it if I could use it with a usb car charger or usb ac charger. Neither works. Nothing exploded or fried or any other cataclysmic event. Nothing happened at all. Zip, zilch, zero, nada. It fits just fine but that's it. :silly:
Its designet to use with external battery pack like Anker® Astro3 10000mAh with 9V / 12V Optional Voltage]
Sent from my A500 using xda premium
FloatingFatMan said:
Considering their claims, I'd hardly call them legit... Seriously.. "Requires a 12v USB port?" There's no such animal...
Besides which, even if you COULD pump 12v down the USB cable to the A500, all you'll manage to do is either a) nothing at all, or b) fry your A500.
Click to expand...
Click to collapse
EDIT: search google for: 'powerusb 12v'
That is not true (while not standard) there is at least one device that can supply 5v-12v over USB: AeroCool PowerPanel with PowerUSB
see the post here: http://www.tomshardware.com/forum/245564-28-powerusb
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(I relaize that is, probably, not what the OP wanted or if it would even fit the inteneded application -- just posting to debunk the statement that no 12v usb port-device exists)
if you soley want to charge via a usb cable: (that is plugged into a usb port on a computer -or-wall wart, etc, with an adapter on the other end to connect to the dc jack on the acer)
Then to match 1.5A current (1500ma) you would need to connect to 3-usb ports (@500ma/port) (like is done for external devices, 3.5" hdd, cd/dvd drives which have two usb connectors [1 for data+power and 1 for just-power])
NeoH4x0r said:
EDIT: search google for: 'powerusb 12v'
That is not true (while not standard) there is at least one device that can supply 5v-12v over USB: AeroCool PowerPanel with PowerUSB
see the post here: http://www.tomshardware.com/forum/245564-28-powerusb
Click to expand...
Click to collapse
Powered USB is not part of the USB standard and is not providing higher voltage or current through a standard USB connector, there is an additional proprietary connector for that. As you can see in the photo.
NeoH4x0r said:
if you soley want to charge via a usb cable: (that is plugged into a usb port on a computer -or-wall wart, etc, with an adapter on the other end to connect to the dc jack on the acer)
Then to match 1.5A current (1500ma) you would need to connect to 3-usb ports (@500ma/port) (like is done for external devices, 3.5" hdd, cd/dvd drives which have two usb connectors [1 for data+power and 1 for just-power])
Click to expand...
Click to collapse
The same current at different voltages does not provide the same amount of power.
1.5A at 5V is only 7.5W, while 1.5A at 12V is 18W, so you would need 7-8 standard USB ports to provide the same amount of power as the standard 12V charger.
power usb
it actually has a usb connector on bottom that is usb standard 5V. and a top connector for the power voltage . It has nothing to do with putting 12v through a standard usb cable.
For one thing the power source has to connect to a regulator in the circuitry of portable devices and that then regulates the charge to the batteries.
Do you think the devices are so smart now that they magically reroute their connections on the motherboard from a usb connector the the power circuits ?:silly:
eppeP said:
The same current at different voltages does not provide the same amount of power.
1.5A at 5V is only 7.5W, while 1.5A at 12V is 18W, so you would need 7-8 standard USB ports to provide the same amount of power as the standard 12V charger.
Click to expand...
Click to collapse
1 standard usb port:
* 5V
* 500 ma (0.5A)
* power = 0.5A*5V = 2.5W
You math is wrong --
3 ports: (not 7-8)
* 5V*3 = 15V
* 500ma*3 = 1500ma (1.5A)
* power = 1.5A*15V= 22.5W (higher than 18W)
8 ports:
* 5V*8 = 40V (way too high)
* 500ma*8 = 4000ma (4.0A)
* power = 4.0A*40V= 160.0W (way too high)[/B]
The device will recieve 15V (+3v higher than the spec)
and will pull upto 18W (from 22.5)
NeoH4x0r said:
1 standard usb port:
* 5V
* 500 ma (0.5A)
* power = 0.5A*5V = 2.5W
Click to expand...
Click to collapse
Corect so far.
NeoH4x0r said:
You math is wrong --
3 ports: (not 7-8)
* 5V*3 = 15V
* 500ma*3 = 1500ma (1.5A)
* power = 1.5A*15V= 22.5W (higher than 18W)
8 ports:
* 5V*8 = 40V (way too high)
* 500ma*8 = 4000ma (4.0A)
* power = 4.0A*40V= 160.0W (way too high)[/B]
The device will recieve 15V (+3v higher than the spec)
and will pull upto 18W (from 22.5)
Click to expand...
Click to collapse
Unfortunatly you can't add the voltages like that, they are the same.
Have a loook at figure 2 and 9 in Power Delivery Design Issues for Hi-Speed USB on Motherboards those give an idea of what the circut behind the ports may look like.

KF OTG Discussion

So I have been playing around with various USB game controllers as well as various storage devices and everything has worked so far (except BT, its detected but thats it). Hashcode has put a low priority on OTG in the kernal dev queue so I would like to get a discussion going about possible hardware solutions to over come the current 3.3v limitation of the USB port when running as a host (which is why devices dont work directly, only through a hub). Someone already suggested a current pump DC-DC in the kernal thread so my current focus something like this: http://www.circuitsathome.com/dc-dc/33v-to-5v-dc-dc-converter
for some motivation to this end, here is my USB NES controller hooked via OTG:
Controller use brought to you by HaiKaiDo Inc. lol
usb otg will work nice if we can up the voltage
usb otg will work nice if we can up the voltage from 3.7 to 5 volt
southbird already did a proof of concept with a voltage regulator from pololu
http://forum.xda-developers.com/showthread.php?p=25943787#post25943787
barrmulio said:
southbird already did a proof of concept with a voltage regulator from pololu
http://forum.xda-developers.com/showthread.php?p=25943787#post25943787
Click to expand...
Click to collapse
Yep saw that. My aim here is to go beyond that and come up with a real design
Sent from my Xperia X10 using xda premium
Can the voltage regulator be wired into the OTG cable? If so I am willing to try this but I need help with the wiring. I am searching now for some type of soapbox enclosure to house the voltage regulator. Any suggestions?
It would serve as the otg cable. The vreg will sit on the power rail between the kf and the normal usb connector. Ultimately, i want to lay out a smd board with the micro usb and regulator that goes in some little enclosure.
Basically what I am thinking of doing is putting the regulator inbetween the micro usb and female usb. It will look like other otg cables but the enclosure with the female usb will be larger.
I am assuming that the red(power) from micro usb is connected to the vout and the red(power) from female usb is connected to vin on the regulator. Do both sides of the ground need to be connected to the regulator or just to each other?
Can this work with GPS receiver?
sent from the greezals fire.
meturne2 said:
Basically what I am thinking of doing is putting the regulator inbetween the micro usb and female usb. It will look like other otg cables but the enclosure with the female usb will be larger.
I am assuming that the red(power) from micro usb is connected to the vout and the red(power) from female usb is connected to vin on the regulator. Do both sides of the ground need to be connected to the regulator or just to each other?
Click to expand...
Click to collapse
You could but IMHO, it would be simpler and cheaper to integrate everything as one device. The OTG cable is nothing special, just a micro USB B to regular USB A. The power needs to run from the micro in the KF to the vReg Vin, vReg Vout to the USB A connector, the ground is connected to all three.
greezal said:
Can this work with GPS receiver?
sent from the greezals fire.
Click to expand...
Click to collapse
No clue. I'm sure a google search would yield some answers
OK I'll look it up now and see if I can get the answer.
sent from the greezals fire.
greezal said:
OK I'll look it up now and see if I can get the answer.
sent from the greezals fire.
Click to expand...
Click to collapse
Just looked it up and not much on the subject have not got a straight answer. Would be great though.
sent from the greezals fire.
Ok, the ones I ordered are in. Size is NICE, it should be really easy to integrate this into existing USB connector enclosures. This is the 120 mA version, the 600 mA version is about twice the size
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altitude909 said:
Ok, the ones I ordered are in. Size is NICE, it should be really easy to integrate this into existing USB connector enclosures. This is the 120 mA version, the 600 mA version is about twice the size
Click to expand...
Click to collapse
very nice - i ordered the pololu one and still waiting for it to arrive
my thoughts were similar; integrate the regulator into the usb female header area of the otg, or somewhere mid-cable...but I'm having a hard time finding an elegant solution to either re-enclosing the plastic end of the female header or enclosing it mid cable
i just back another otg cable today, i'll be cutting it apart to see if there's enough space by the usb a
success! kinda.. For super low current devices (i.e. NES game controller) it is working fine, anything larger (flash memory) its drawing too much current causing the voltage to sag below 2.5V which is not enough to power the regulator. Will try the LTC3426 one tomorrow since that should be able to operate at a lower input voltage
altitude909 said:
success! kinda.. For super low current devices (i.e. NES game controller) it is working fine, anything larger (flash memory) its drawing too much current causing the voltage to sag below 2.5V which is not enough to power the regulator. Will try the LTC3426 one tomorrow since that should be able to operate at a lower input voltage
Click to expand...
Click to collapse
just to make sure I got your wiring right
from micro usb b
- red to vReg Vin
- pin 4 to ground
- pin 5 to ground
from usb a
- red to vReg Vout
- black/pin 4 to ground
?
my stupid otg cable doesn't have standard colors (it's green, blue, yellow, red, yellow&red), so other than vcc i'm not sure what's what (edit: now i think blue is gnd and yellow/red is sense, yellow is d-, green is d+).
I was also expecting the otg short to be on the micro side and not on the usb a side, but it wasn't
my idea is to have the regulator sit inside the hollowed out area of the female header seen on the bottom left
Just take a meter and see what is connected to what. It does not matter where pin 4 and 5 are shorted.
Unfortunately, it looks like without some sort of magic, the port on the kf cannot supply enough current to drive these regulators. Im observing the same thing as southbird did, the devices show up but do not work. Measuring the voltages at the power pins with a flash drive connected i get 2.4v at the vreg input and 4.5 at the output which means that there is too much load. Time to start looking for battery powered usb hubs
this battery charger or this usb charger both work well for me with a y usb cable...i've seen some other posts with folks that just wired right into the charger, e.g. here
ok, the regulator arrived today and i played around with it
the otg cable was too frail for my poor soldering skills to do properly, so i ended up cutting up a usb extension cable to about 1' in length and soldering it halfway...i'll enclosure in heat shrink later
my results were pretty much the same as southbird and altitude909
My 8Gb centon usb however mounts perfectly *every* time, however my 4Gb, 2Gb or 512Mb sticks will not mount. When I try the elago w/ a 32Gb micro it conks out mounting as a whole, requiring a reboot of the KF to remount the 8Gb stick (probably some kernel protection)
so you need a regulator to get flash drives to work? that explains why it never worked for me lol

UART Access on Sprint Optimus G

Hi,
I'm making this thread because i have seen alot of bricks for this phone including my own. What seems to be most annoying is, my phone boots, shows LG Logo splash and after that completely black screen whereas flashing the Mako (Nexus4) Rom via LGNPST works, it boots without any issues. So the idea is to see the startup log and identify whats been causing the problem in actual.
The UART pads on this phone are completely not made to be accessible by normal means and below is an attached pic of the same
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As you can see, the molex is just barely a cm long and contains 15pads on each side. The problem is however, m not very much familiar with UART/Serial stuff. I have hooked up a serial connection with the pogoplug sometimes back and all m aware of is basic programs used and Profilic USB-Serial converter (Nokia CA-42 Data cable in mycase). Right now i'm having a USB-RSR232(Com Port) converter at my place and i'm unable to get any outputs to putty/terminal. Any info regarding this will be hugely appreciated.
I know nothing about the specifics of this phone,
but be aware that many UART interfaces are not at 5V levels but at 3.3V, 2V or lower.
What does a voltmeter say on the TXD pin?
I got my Nook's kernel console UART working using a home-brew/cheesy RS-232 converter.
I don't even remember what the levels are, but it works fine.
Thanks for the reply, i will to gather the readings later today. One more question, the current Signal converter m having right now i.e, USB-RS232 will work or do i need to get anything else?
If I read that correctly, you only have a USB to RS-232 converter?
Regular RS-232 swings at least + and - 5V and will blow things out.
A "data cable" usually uses "TTL level" which swings between ground and some fraction of +5V, maybe 3.5V, 2.8 being the nominal threshold.
I've got one for a GPS puck that uses a Prolific chip.
I've used that as a debugger hookup for an ATMega32u4 which runs on 5V.
Nowadays I have a couple of transistors on a board for going from my Nook to a regular PC RS-232 input.
Below readings were taken with battery and USB cable connected.
TX- 0.03v ~ 1.65v
RX- 0.03v ~1.65v
Click to expand...
Click to collapse
i'm having a Profilic USB-Serial converter which is having a USB type B connector and a com port connector on each sides. I'm only connecting the RX and TX wires on the phone's board to gain direct access to UART rather than using USB type data cable. Phone is powered by USB and battery.
If you want a pre-fab solution you can use a Bus Pirate:
http://dangerousprototypes.com/docs/Bus_Pirate
That will handle low voltage.
The thing is, even at 115.2 kbaud, your signal is so low speed that you don't have to get that serious.
When you are talking about the USB connected, do you mean the phone's USB adapter?
Those TXD & RXD readings were measured with nothing connected?
funkym0nk3y said:
I'm only connecting the RX and TX wires on the phone's board to gain direct access to UART rather than using USB type data cable. Phone is powered by USB and battery.
Click to expand...
Click to collapse
You should connect ground of the phone with ground of your serial-converter/PC.
Ground is connected from the PC, i have tried with connecting ground from riff box, no help.
Renate NST said:
If you want a pre-fab solution you can use a Bus Pirate:
http://dangerousprototypes.com/docs/Bus_Pirate
That will handle low voltage.
The thing is, even at 115.2 kbaud, your signal is so low speed that you don't have to get that serious.
When you are talking about the USB connected, do you mean the phone's USB adapter?
Those TXD & RXD readings were measured with nothing connected?
Click to expand...
Click to collapse
RXD and TXD readings were taken with both USB cable from PC and battery connected.
btw how did you find/identify the UART-pins and why are sure that you have the correct pins?
I'm very interested in this process because I have an Xiaomi MI2 with nearly the same hardware.
i located them using the service manual so m indeed sure they are correct.
M having this converter
and i guess that is perfect for serial output, but the thing is m still unable to get any outputs from the phone, i'm attaching the svc manual for the same incase some1 is willing to help out.
http://d-h.st/agQ
The UART is accessible via 3.5mm earphone jack in Nexus 4 and not in any of the og variants.
Well, your adapter is fine and dandy, but I don't see any photos of a level shifter.
If you connect some of the DB9 pins on that adapter to something inside your cell phone you are going to blow something up.
See this post for a photo of my setup: http://forum.xda-developers.com/showpost.php?p=35328483&postcount=11
Hey, thanks for the reply, m not connecting the pin9. M just connecting the pin2 and pin3 on rx and tx pads of my phone,below is a pic of my current setup.
That last photo does not look like the first photo.
I'm not talking about pin #9, I am talking about the 9-pin connector.
Yes, you should be using pins #2, #3 & #5 but don't connect them directly to your phone!
What comes out of the 9-pin connector is higher voltage that will blow out the circuits on your phone.
You measured it yourself, the phone works on levels less than 2 volts.
Now measure what is coming out of the 9 pin connector.
Scary, eh?
You need a level shifter.
Besides the voltages being different, the polarity is different.
I guess this should be fine ?
http://www.ebay.com/itm/New-JY-MCU-...157?pt=LH_DefaultDomain_0&hash=item5aebfc73f5
funkym0nk3y said:
I guess this should be fine?
Click to expand...
Click to collapse
No, that is a [5V logic level] <=> [3.3V logic level] converter.
What's coming out of the 9-pin connector is [RS-232 level].
What your phone wants apparently is [2.5V logic level]
So what you need is a [2.5V logic level] <=> [RS-232 level] converter that inverts.
Here, in summary are the logic standards:
Code:
Standard Zero One
---------- ---- -----
RS-232 5.0V -5.0V (notice that this signal goes [b]minus[/b])
Cheesy 5.0V 0.0V (we're cheesy and don't have a minus supply)
5V logic 0.0V 5.0V
3.3V logic 0.0V 3.3V
2.5V logic 0.0V 2.5V
If you have a "USB data cable" that uses "TTL levels" [5V logic level]
then all you would need would be a [5V logic level] <=> [2.5V logic level] converter.
If you want to stick with your 9-pin adapter you will have to have something that converts from/to [RS-232 level].
If you were building this thing seriously, you would use a MAX232 chip or something that would convert from/to [5V level].
If you were going to be cheesy, you can drive your 9-pin connector with [Cheesy level].
This is logic which does not meet the spec for [RS-232] level but is "good enough" to work.
I mean, what is it that you want out of this? 90% is to get a log out while booting.
Then you only have to do one side of the deal, a [2.5V level] => [Cheesy level] that inverts.
Enough for now...
Reading this thread, I'd be surprised if you have not already blown-up something in your phone. Randomly connecting HW to the inside of your phone without knowing the difference of +/- 15V RS-232 levels and 1.8V CMOS logic is a sure killer!
But if its still working...here are a few comments:
1. We'd need to see the entire PCB, to help you identify the proper UART ports.
2. If it's based on Qualcomm, and anything similar to their reference design, you probably don't even need to go inside to get debug output. You might be able to get it via a modified micro-USB jig...
3. You say you have schematics, why don't you post that instead?
4. Get yourself a proper serial cable, ASAP. (You will for sure find other occasions where it is useful.) I always preach for the FTDI products...
5. The port you show, look like a JTAG port...or is it a strip-connector?
6. Never, ever, solder directly to your PCB, use connectors!
Nothing is damaged, i already measured the voltage coming out from rx and tx of the converter which i connected with the phone, however i was not aware that i might need to use a level shifter and m sure that might be the deal breaker. Anyway, i got my phone running after 3weeks and would like to use it normally for sometime now, i will be doing the this again once i get the proper setup at my place. Also the UART ports are correct as they are obtained by the service manual.
I have posted the service manual in the thread to avoid all the confusions already. Finding the receptacles is not easy for me as i'm unable to find them locally or online, samsung receptacles are easily available here in my country but they aren't seems suitable for this molex thats the only reason i did soldering on the molex legs itself.. Yes you are correct, the port which is posted is a jtag port and the wires connected are coming from my jtagbox.

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