Everything you Ever Wanted to know about Serial - TTL

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Murrkf
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PostPosted: Tue Aug 18, 2009 19:42    Post subject: Everything you Ever Wanted to know about Serial - TTL Reply with quote
I can't tell you much about this. But there are some routers that are sans jtag and serial is the only way to recover them. So.....I just got this little device today and will document my getting to know how to work it. Hopefully those with more experience can answer my questions and together we can put together a thread that will help others.

First thing I notice is that the threaded connections to the right and left of the nine pins on the RS232 side block it from being able to be plugged in to the 9 pin male on my computer. Ahh. I should get a connector cable, I say to myself.

When I go looking for one, I see that there are serial/usb adapters. Hmmm. Methinks. Does this mean I can hook this up to a USB? We all know that USB to 25 pin parallel for Jtag doesn't work well (at all), so my first question is whether I can use a USB adapter on this unit, and plug it into a USB port, or do I need a nine pin connector?

Second question....what are people using for the four pin connectors. Is there a particular ribbon cable that fits well.

This thing is small. Slightly wider than and SD card and not quite as long.

So let's talk serial connectors. Anything and everything. If you know something, post it here.

Here is some serial Pinouts, provided by EKO (you want to connect to TX0/RX0 NOT tx1/rx1):

http://www.dd-wrt.com/phpBB2/viewtopic.php?t=12879



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Last edited by Murrkf on Sun Sep 06, 2009 15:26; edited 2 times in total
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DHC_DarkShadow
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PostPosted: Tue Aug 18, 2009 19:57    Post subject: Reply with quote
I use a USB TTL Converter.

I will follow this tread as well to see how this compares to your converter as far as functionality.



USBpinouts.jpg
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all the pinouts. The 5v is NOT used for my TM.
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Included cables
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Bought off ebay it was a kit
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fggs
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PostPosted: Tue Aug 18, 2009 20:00    Post subject: Reply with quote
If I'm not wrong it uses MAX232 and for my point of view you can attach it directly to your serial port and connect the cables separetely. I think is more pratical than a built-in cable.
barryware
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PostPosted: Tue Aug 18, 2009 20:04    Post subject: Reply with quote
I use a USB to serial adapter. The USB to serial adapter ends up with a com port in the device manager. Then I plug the ttl adapter into that.

I did find that not all usb to serial adapters are created equal. I had one (usbgear) that worked fine on the TM. However it didn't work on a V8. I thought that even though the V8 had the physical port, that serial was not available.

One of the devs confirmed that the V8 DOES have a serial port. I have a usb to serial adapter on a UPS to connect to my rig that is missing a real serial port. I gave that adapter a lash and it worked on the TM, the V8, a G2 V1.3, and anything else I tried.

In regards to the wire hookups. I'll post a pic later as to what I used 1st, and what I use now.. I got a few pics on the forum somewhere.. I'll find the link.. This is an old setup though.

The device I use: http://alldav.com/index.php?main_page=product_info&cPath=9&products_id=11

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Last edited by barryware on Tue Aug 18, 2009 20:11; edited 1 time in total
fggs
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PostPosted: Tue Aug 18, 2009 20:08    Post subject: Reply with quote
Some USB-to-Serial chips are crap, they are really sensitive to noise and it will work sometimes and sometimes nothing. I like FTDI chips, works well for me.
Murrkf
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PostPosted: Tue Aug 18, 2009 20:15    Post subject: Reply with quote
I bought mine on ebay under this description:

RS232 Serial Port To TTL Converter Module MAX3232

However, I notice now that it arrived that the pins aren't marked. It is supposed to be 3.3 and 5v (auto).

Anyone know which pin is which?

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barryware
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PostPosted: Tue Aug 18, 2009 20:25    Post subject: Reply with quote
Murrkf wrote:
I bought mine on ebay under this description:

RS232 Serial Port To TTL Converter Module MAX3232

However, I notice now that it arrived that the pins aren't marked. It is supposed to be 3.3 and 5v (auto).

Anyone know which pin is which?


No docs? That could be a problem.. You could trace the pins to the max chip and figure it out. Schematics are all over the place. Ground aught'a be easy to spot.. It will be one of the four pins. Razz

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Murrkf
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PostPosted: Tue Aug 18, 2009 20:41    Post subject: Reply with quote
barryware wrote:
No docs? That could be a problem.. You could trace the pins to the max chip and figure it out. Schematics are all over the place. Ground aught'a be easy to spot.. It will be one of the four pins. Razz


No visible trace... Crying or Very sad

Multimeter should tell me power and ground.

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fggs
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PostPosted: Tue Aug 18, 2009 20:41    Post subject: Reply with quote
Anything at the bottom of pcb? Razz
barryware
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PostPosted: Tue Aug 18, 2009 20:43    Post subject: Reply with quote
Murrkf wrote:
barryware wrote:
No docs? That could be a problem.. You could trace the pins to the max chip and figure it out. Schematics are all over the place. Ground aught'a be easy to spot.. It will be one of the four pins. Razz


No visible trace... Crying or Very sad

Multimeter should tell me power and ground.


I can see them in the picture you posted.. Put a flashlight behind (or in front of) the pcb :wink:

http://sodoityourself.com/max232-serial-level-converter/

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Murrkf
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PostPosted: Tue Aug 18, 2009 20:53    Post subject: Reply with quote
fggs wrote:
Anything at the bottom of pcb? Razz


those soldered connections are for the rs232, not the Max232 chip.



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Don't think I can see the trace here...Okay...MAYBE the bottom pin goes to the bottom right chip pin, and the second pin up goes to the chip pin just above the bottom right
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_________________
SIG:
I'm trying to teach you to fish, not give you a fish. If you just want a fish, wait for a fisherman who hands them out. I'm more of a fishing instructor.
LOM: "If you show that you have not bothered to read the forum announcements or to follow the advices in them then the level of help available for you will drop substantially, also known as Murrkf's law.."


Last edited by Murrkf on Tue Aug 18, 2009 21:07; edited 2 times in total
barryware
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PostPosted: Tue Aug 18, 2009 20:53    Post subject: Reply with quote
who's you buddy? Cool
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Murrkf
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PostPosted: Tue Aug 18, 2009 21:10    Post subject: Reply with quote
barryware wrote:
who's you buddy? Cool


You da MAN!

So I have a usb/serial connection somewhere...have to find it...but what to I connect to the 4 pin .0010 connector? Any cable that works well?

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I'm trying to teach you to fish, not give you a fish. If you just want a fish, wait for a fisherman who hands them out. I'm more of a fishing instructor.
LOM: "If you show that you have not bothered to read the forum announcements or to follow the advices in them then the level of help available for you will drop substantially, also known as Murrkf's law.."
fggs
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PostPosted: Tue Aug 18, 2009 21:16    Post subject: Reply with quote
I don't know if I'm disturbing your thread but I'm bored and this forum is my start page for some time, so I will answer: I use old case cable, like power led cables, hdd led.. works pretty well.

Off-topic: this svn update from source never ends Sad 3 days of waiting
Murrkf
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PostPosted: Tue Aug 18, 2009 21:22    Post subject: Reply with quote
fggs wrote:
I don't know if I'm disturbing your thread but I'm bored and this forum is my start page for some time, so I will answer: I use old case cable, like power led cables, hdd led.. works pretty well.


Nope. Any and all input is welcome. I found my serial cable. It was on my desk. I think it has the ftdi chip. I plugged it in *but*....I have a mac OS running. Might have to flip my system over to windows.



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_________________
SIG:
I'm trying to teach you to fish, not give you a fish. If you just want a fish, wait for a fisherman who hands them out. I'm more of a fishing instructor.
LOM: "If you show that you have not bothered to read the forum announcements or to follow the advices in them then the level of help available for you will drop substantially, also known as Murrkf's law.."
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