Emmc online reading through card reader help

[Davi.p]

Yes, i'm trying to do it the second time, the second unsuccess, someone knows the common errors when do it? I am connecting with CMD, CLk, D0, GND, powering the board from a power supply, i have board schematic and the test point on marked resistors.
Thanks!

[CapLeaker]

Re: Emmc online reading through card reader help

Reading and writing an EMMC onboard? Read my Dreamlink T1 thread. There I did read and write to the EMMC on the board with flying wires and off the board with an adapter.

[Davi.p]

Re: Emmc online reading through card reader help

My goal is to program with card reader not RT809H, that is too easy! Until now the only difference seen is that i have soldered only one pin to ground of the quartz, but one guy does it so in a video.. when guys in videos puts the usb reader in the pc with windows recognizes the memory as a normal flash usb storage, in my case can't happen because i wiped all that via uart commands (an error), but the registers must be there intact so things like size, model, vendor could be readable i think, i used eFixer emmc tool software, a tool seen in the videos, for OPPO cellulars servicing, not windows nor the tool makes a change.. f**k..

[Davi.p]

Re: Emmc online reading through card reader help

i have found 2 broken resistors on the D0, CLK lines, them are marked 0 ohm on the diagram but marks mega ohms, in particular D0 losts connection with both cpu and pullup resistor, CLK with cpu+pulldown.. them had probably been heaten too much with soldering iron

[Davi.p]

Re: Emmc online reading through card reader help

changed the resistors, same zero results, i have noticed a tension of 0v on the D0 resistor that is still good, that is strange.

[CapLeaker]

Re: Emmc online reading through card reader help

Check out the other resistors on the other data lines like D1, D2 etc. They are the same. I did the same thing somehow on the Dreamlink. It’s evident what happens when you look at the data line with an oscilloscope.

[Davi.p]

Re: Emmc online reading through card reader help

but to connect in line mode i use only one data line (D0), i was wondering if there is a reset line problem, from a datasheet i read yesterday of an emmc model, the reset signal must be present, i have not connected it, if the processor is off (quartz tied to gnd) that is not present, this is why i have removed the quartz short circ. , but this way the processor generates another clock for the emmc that is surely different from the one from card reader (the less the data lines, the less is the frequency) so probably a conflict, youtube videos shows no quartz cut out, them are portable devices not tv.. how can i escape from this corner? i have no reset signal on the card reader.. the reset signal is not as simple as pull it up to 3,3v, i read that before this the host must set a register before..

[CapLeaker]

Re: Emmc online reading through card reader help

You cannot run two clocking signals at the same time. It will not work. The clock crystal on the EMMC board must be disabled. I am starting to wonder about that YouTube video you’re referring to.

[Davi.p]

Re: Emmc online reading through card reader help

You can see them searching "emmc isp tool"
next try i will reconnect ground to quartz and shorten the wires

[Davi.p]

Re: Emmc online reading through card reader help

i have shorten the wires to 10cm, tried to start with quartz connected then access it with quartz grounded, checked other resistors, there is one high ohms but i'm not really sure is ko, my first suspect was the d0 line that marked 0v, now i have changed again resistor with a 33ohm right size, now it marks 1,1v, that is no good for me, i have same volt also on CMD and other data line.. i am confusing myself more and more, i want to hit the board with head!

[Davi.p]

Re: Emmc online reading through card reader help

even though i suspect original D0 resistor was right 1M6 it is also strange that i have 0v on it

[CapLeaker]

Re: Emmc online reading through card reader help

On both sides?

[Davi.p]

Re: Emmc online reading through card reader help

yes, unfortunately those ultra tiny resistors when touched with my usb soldering iron are too sensitive to heat and them fries, i don't have many sources of those sizes spare parts.. would be ok if i had a temp controlled iron