View Single Post
Old 12-30-2011, 12:19 PM   #16
Carpe diem, c'est la vie.
geekmaster ought to be getting tired of karma fortunes by now.geekmaster ought to be getting tired of karma fortunes by now.geekmaster ought to be getting tired of karma fortunes by now.geekmaster ought to be getting tired of karma fortunes by now.geekmaster ought to be getting tired of karma fortunes by now.geekmaster ought to be getting tired of karma fortunes by now.geekmaster ought to be getting tired of karma fortunes by now.geekmaster ought to be getting tired of karma fortunes by now.geekmaster ought to be getting tired of karma fortunes by now.geekmaster ought to be getting tired of karma fortunes by now.geekmaster ought to be getting tired of karma fortunes by now.
geekmaster's Avatar
Posts: 6,433
Karma: 10764860
Join Date: Nov 2011
Location: Multiverse 6627A
Device: K1 to PW3
Originally Posted by MatzeMatz View Post
About the 1.8V USB <-> serial adapter:
Any suggestion about how I can detect if it's compatible (1.8V) adapter?
What about the "Digitus DA-70156"?
(e.g. from German Amzon: Digitus DA-70156)
Or any other suggestions?
The model at the link that you provided (above) has a 9-pin D-connector, which is used by RS-232 serial (not TTL serial).

Be sure NOT to get one that is for RS-232, because that puts out up to +12v for logic ZERO, and -12v (negative) for logic ONE. Although that can be converted to 1.8v TTL, the simplest circuit needs at least two transistors and additional components to invert the logic levels and shift the voltage levels.

If it supports 1.8v TTL then it should say so in its list of features, or somewhere in its documentation or sales information.

If in doubt about a particular device that you plan to purchase, you should contact the manufacturer or vendor of that device and ask them, before making that purchase.

The least expensive (mostly-compatible) adapters that I have found are on eBay for under $3USD with free shipping, but they need the modifications detailed in my "Kindle serial adapter level shifter circuit" thread:

If you watch "Unbrick your Kindle 3 - Video" by Seaniko7, you will see a details about the USB 1.8v TTL serial adapter cable that he used:

EDIT: It is difficult to search for a USB 1.8v TTL serial adapter because many adaper cables are 1.8m long.

There was a discussion about this on the IRC channel.

Disclaimer: The following information (protected by the Spoiler wrapper) is public information, relevant to this thread, with participation by mobileread members, so there should be no problem posting it here. It contains some "salty" language, so please do not read it if that might offend you. Thanks.

Here is an excerpt of that IRC channel discussion:
dasmoover 	: kindle is f**ked up to the point where it only reads two items, lets me go to screensaver, wifi won't connect, no keyboard	Today - 7:47
geekmstr 	: any attempt to access /mnt/us sent "Stale NFS mount" message to serial port / logs...	Today - 7:47
geekmstr 	: do not waste you time without serial cable (unless you enjoy this)	Today - 7:47
geekmstr 	: get serial cable.	Today - 7:47
dasmoover 	: LOL	Today - 7:48
geekmstr 	: seriously.. what LOL?	Today - 7:48
dasmoover 	: I need materials	Today - 7:48
geekmstr 	: you ENJOY this?	Today - 7:48
dasmoover 	: not at all	Today - 7:48
dasmoover 	: but I have no clue on the hardware necessar	Today - 7:48
Overshee 	Quit: Be back later	Today - 7:48
geekmstr 	: what materials? what do you have? can you afford a 1.8v usb serial adapter?	Today - 7:48
dasmoover 	: sure	Today - 7:48
dasmoover 	: where?	Today - 7:49
geekmstr 	: 3.3v adapters are like $3 shipped from singapore. 1.8v I do not know where -- Seaniko7 shows one in his k3 unbriking video...	Today - 7:49
dasmoover 	: what other hardware do i need	Today - 7:49
geekmstr 	: there is a thread with schematic on converting 3.3v to 1.8v.	Today - 7:50
WafflesVa 		Today - 7:50
geekmstr 	: quickest to just solder wires to the serial pins with a needle-tip soldering iron (not too hot).	Today - 7:50
geekmstr 	: best way is the special connector. I have 6 free samples on their way here. yifanlu has 20 in his posession.	Today - 7:51
geekmstr 	: The special crimp tool is $300 so you need to cut and solder the pins like hondamarlboro did (look at his photos).	Today - 7:51
geekmstr 	: the pins (sockets) in the connector that is...	Today - 7:52
geekmstr 	: there is a lot of discussion in the irc archives too..	Today - 7:52
n00b596 	: hardware junkies...I have a root shell. I win.	Today - 7:52
geekmstr 	: I helped several ppl get their comm working (or at least one way)...	Today - 7:53
dasmoover 	: mm ive got to order the materials	Today - 7:54
geekmstr 	: dansmoover -- what country are you in?	Today - 7:54
dasmoover 	: us	Today - 7:54
geekmstr 	: what state?	Today - 7:56
dasmoover 	: ny	Today - 7:56
geekmstr 	: I am in MN	Today - 7:56
geekmstr 	: here is digikey 1.8v:	Today - 7:56
geekmstr 	:	Today - 7:56
geekmstr 	: @25 + shipping.	Today - 7:56
geekmstr 	: $25	Today - 7:56
geekmstr 	: looking on ebay	Today - 7:57
Tr0n 	: why is it so expensive?	Today - 7:58
Tr0n 	: couldnt you just take apart an existing serial cable?	Today - 7:58
Tr0n 	:	Today - 7:58
geekmstr 	: digikey sells to big companies.	Today - 7:58
geekmstr 	: Your URL is RS232 -- logic 0 = +12v, logic 1 = -12v. TTL logic 0 = 0v, logic 1 = supply voltage (1.8 or 3.3)	Today - 8:00
geekmstr 	: You would have to hack the rs232 one to find ttl somewhere inside it (too much work and no guarantee of success).	Today - 8:01
geekmstr 	: better to get ttl	Today - 8:01
dasmoover 	: looking how to get the kindle into diag/reset with hardware commands	Today - 8:01
geekmstr 	: Get this:	Today - 8:04
geekmstr 	: $2.92 buy-it-now free shipping. hong kong though -- will take a month...	Today - 8:04
n00b596 	Quit: Page closed	Today - 8:05
geekmstr 	: needs voltage conversion as shown in my schematic on the thread (including removing an LED from it).	Today - 8:05
geekmstr 	: Or more money locally if in a hurry.	Today - 8:05
geekmstr 	: 1.8v not an ebay keyword match...	Today - 8:06
DoYouKnow 	: is there a way to view 3g UARFCNs on a kindle without opening the case?	Today - 8:08
geekmstr 	: TI has a small computer (430 launchpad) that costs $4.30.	Today - 8:10
geekmstr 	: It is a computer that can do many things. one of them is to act like a usb serial adapter.	Today - 8:10
geekmstr 	: I have several of these.	Today - 8:10
geekmstr 	:	Today - 8:10
geekmstr 	: An awesome bargain, sold way below cost to get programmers to write stuff for them.	Today - 8:11
geekmstr 	: a full development kit with mutliple CPU chips (swap them on the board)	Today - 8:12
geekmstr 	: it has a bunch of generial purpose i/o pins. there is code to use a couple for serial RxD and TxD.	Today - 8:12
dasmoover 	: how would I use it for k3	Today - 8:12
geekmstr 	: They are in US and ship fast.	Today - 8:12
geekmstr 	: K3 has serial connect open to outside, in bottom slot in left side. Read here:	Today - 8:14
dasmoover 	: if i bought this, what else would I need for serial access?	Today - 8:15
geekmstr 	:	Today - 8:15
geekmstr 	: The 430 comes with usb cable for power and PC communication. The kindle would connect to some pins on the board but probably needs the diodes and resistor shown in my schematic (not 1.8v).	Today - 8:16
geekmstr 	: You need to load a usb serial program into it to make it do that. A learning curve.	Today - 8:16
geekmstr 	: Much less learning if you just get a real serial adapter that installs as a com port...	Today - 8:17
dasmoover 	: so i'd need to get that, a couple of resistors and diodes, create pcb board?	Today - 8:17
geekmstr 	: but if you WANT to learn the 430 is the way to go.	Today - 8:17
dasmoover 	: i'm trying to find the easiest way to be honest	Today - 8:17
geekmstr 	: if you want cheap but simple the $3 chinese one is the way to go.	Today - 8:17
geekmstr 	: If you want simple and fast the digikey one is the way to go.	Today - 8:18
geekmstr 	: cheap, easy, fast shipping -- pick only two...	Today - 8:18
geekmstr 	: cheap+easy = chinese + 30 days.	Today - 8:18
dasmoover 	: east, fast shipping	Today - 8:19
geekmstr 	: cheap+fast = TI 430 + big learning curve	Today - 8:19
dasmoover 	: cheap, easy	Today - 8:19
geekmstr 	: easy+fast = digikey $25 + shipping	Today - 8:19
geekmstr 	: cheap+easy = ebay chinese $3 free shipping 30 days (by boat)	Today - 8:19
geekmstr 	: and make a connector like this:	Today - 8:20
geekmstr 	: and make the voltage convertor in my schematic. and remove an led from the adapter.

Last edited by geekmaster; 12-30-2011 at 12:49 PM.
geekmaster is offline   Reply With Quote