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Originally Posted by WaseemAlkurdi
I myself believe that it's 3.3v-tolerant. However, I do understand your concern.
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I'm still wondering whether i should take the chance or not, it would save me the time waiting for parts...
Quote:
Originally Posted by WaseemAlkurdi
Why order parts? Why not simply solder in the resistors as per the level-shifter circuit? It's literally two resistors and a diode. Beats waiting for parts.
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That's the thing, where am i supposed to get the resistors and diode, whichever way i take i need parts, i got nothing at the moment as i don't do this often.
Quote:
Originally Posted by WaseemAlkurdi
You mean the AMS1117 LDO regulator. Never used it myself, nor I ever saw it being used on this forum. Theoretically, it would work, but how is it different to using a simple resistor?
And since you're buying parts, wouldn't it be better to just buy a new serial cable that provides 1.8 volts out of the box with no modifications?
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I just googled regulator vs resistor that's how much i know about this stuff lol , i guess a resistor does makes more send at the point but the price for a regulator is a very small margin and it's 1 part instead of 2 resistors right?
Regarding the serial cable:
1. those are expensive
2. i honestly like to improve my skills and this job fits perfectly for this as there is low risk to mess something up
Quote:
Originally Posted by WaseemAlkurdi
As for the picture, it's definitely odd. In my setup, I never touched the jumper pins, except to set the jumper to 3.3 volts. I guess that the owner of the picture used the jumper pins as a 3.3v source either out of ignorance of the jumper's use, or deliberately, possibly because they had lost the actual jumper itself. But there's no need for a 3.3v source. The 3.3v are provided over Tx and Rx.
Edit: After having re-read the article, he's using that to supply the 1.8 volts to the Tx and Rx pins. That 1.8v comes out of that black box, the LDO regulator, on the backside of the board.
Again, why not buy something that provides 1.8v out of the box?
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i would if it was cheap
Quote:
Originally Posted by WaseemAlkurdi
To recap, you only need three cables going out of that board:
1. Board Rx -> Kindle Tx
2. Board Tx -> Kindle Rx
3. Board Ground -> Ground.
Not a single cable is needed on top of that.
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Quote:
Originally Posted by WaseemAlkurdi
Whatever that extra cable is, it definitely isn't connected to the Kindle's serial port pad. It seems to be going to a screw on the Kindle's board, probably taped over the screw instead of wrapping it round the screw the way it's supposed to be done. If that's what happened, it would be another ground cable, but there's already another ground cable soldered to the RF shields (the metallic boxes on the board).
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Why would anyone need 2 ground connections?
Quote:
Originally Posted by WaseemAlkurdi
I'd rather open up my Kindle every time (and how many times is that going to be?) rather than permanently disfigure it with a hole to the outside. I thought of sticking the cables out as a compromise, but even that is ugly.
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I can relate to this but opening every time can also be bad and annoying i guess it really does depend on how often it happens to justify.
Quote:
Originally Posted by WaseemAlkurdi
With serial, you are going to flash the individual partitions. Even if you flash your Kindle with the wrong partitions, it's not going to do the Kindle any harm, because you can always flash them again with the correct image via fastboot.
A word of caution though: Modifying the bootloader (U-Boot), which is located outside of user-accessible flash storage, is risky. But IIRC, an Amazon stock update package won't touch that.
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I've seen some people erase all and then could not recover from it , i thought i'd ask