For reading down, how much voltage applyed, can you draw what signal goes where on that usb and also on board. You used windows or linux to read down it ?
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
For reading down, how much voltage applyed, can you draw what signal goes where on that usb and also on board. You used windows or linux to read down it ?
Plasmid_Boy
Member
For what it’s worth, Rooter, Sid, TonyT, I admire and appreciate what you guys have done and do. It must have been fun trying to figure things out and rest of us benefit from your clever work. Cheers!
One goes to power supply ground, the other one to the SD-card reader ground.
Furthermore if you take a close look, you can see that I used multiple ground wires. Between adjacent signal lines coming from the SD card reader I always put one VSS/GND or VCC line. For practicality reasons I connected those at different (ground) points on the Tegra board (e.g. on a ground pad besides the C673 label).
The pinning is exactly that what was shown in the beginning of this thread: Successful data recovery of broken eMMC chip MCU1
Except that I used multiple VSS/GND connections (just to be on the safe side).
I used ddrescue on Ubuntu 18.04 LTS and on macOS 10.13 (HighSierra) ...
The USB device is a simple microSD-card reader which I modified (removed the contact-springs and soldered wires instead).
I set the voltage to 2.7 V, the current drawn in this case was about 750 mA (you can see it in the display of the power supply in one picture). When using 2.8 V, the current goes up to about 900 - 1000 mA.
Note: I did NOT connect the VCC line of the SD-card reader (which was at 3.3 V). So this is kind of a hack, because the reader expects 3.3 V logic levels, but the eMMC can only provide 2.7 V (because of me only feeding it 2.7 V). If you wanted to build a really proper connection, you would need a level bidirectional level-shifter (I ordered one, but decided to give it a try without it - and it worked).
Last edited:
Is there a voltage where the current decreases below 1 A? Did you double check your wiring?ok i setteed my lab psu too 2,7v and got over 1A draw
Just a thought: If the CID contains multiple power converters (to generate different voltages like 3.3/1.8/1.2 etc.), then there is most likely something like a power monitoring device which keeps the SoC in reset until all the power rails are stable. It would probably be easier to search for something like that.
Slexs
Member
Thank you everyone for great additions to this wealth of knowledge. One quick question, does anyone here know what the connections circled in red are? Is this an additional GND and VCC connection point?
You can check continuity using an ohmmeter, to the known Vcc and Vss pads.
