[How-To] Serial debug connection

hi zoorider,

the fact that you see a/some character is a good thing.
You might want to try and adjust your connection speed at first.

At what speed are you currently connected?

ps, what do you own? FE/SE/RE ?

Hi evow04,
My m8 is FE version, currently i connect with 115200 (8E1).
Same result when try with minicom on ubuntu.

Ok, try to lower it, it might do the trick.

And is it a usb or serial TTL, is it powered by m8 or..?

I bought "USB to RS232 Module TTL UART Converter" from ebay.
(ITEM NUMBER: 270577022238)
--
And connect 3 wires to M8 (TX/RX/GND).

take 3v from external power source. m8s didnt wirked 4 me.
If you see charackter which are getting more and more while starting m8 you are on a very good way.
Have a look if something comes when you tap the screen....
Then just try some of the baudrates. If this doesnt work it coulod be that your contacst are not completely right

alright, that is a tool that should work.

I supose that lowering the speed makes no difference?
If not:
*What are the other connection settings?
*Could you upload a screenshot of the character?
*shorten TX with RX, send a character in the terminal and see if it returns?

Hi, Putty Output capture here.
@flickr.com/photos/15279724@N00/4644343873/

- Putty Config
@flickr.com/photos/15279724@N00/4644343943/in/set-72157624023131605/

- Win7 Device config
@flickr.com/photos/15279724@N00/4644960198/in/set-72157624023131605/

Sorry, i've problem with url post.
"You are only allowed to post URLs to other sites after you have made 15 posts or more."

All speed return same result, and USB2TTL is work on loopback test.

Putty Output capture here.
@flickr.com/photos/15279724@N00/4644343873/

It is good to see this,
I am suspecting that it could be putty related, so try to use DNW.EXE ?
If that doesn´t work out it might be that you wrongfully connected TX/RX,
so make sure to check this!
An other option is that there might be an option inside your debug tool
that normally is there for recovery but screws your data on the m8.
I remember R3wdy had this with his tool, will try to find his post about it.

All speed return same result, and USB2TTL is work on loopback test.

Those settings are fine, they did the trick on my device in the past.
So if lowering speed doesn´t help you might want to try an other power source like r3wdy mentionned.
(normally you would have a jumper on the TTL that can chose external power (battery or m8 serial) or internal power (coming from usb port))

So try to play with those tricks.

Sorry, i've problem with url post.

no problem, you are halfway the process ;-)


edit,did you try the loopback also with the plug that goes in the m8?
To check wiring like r3wdy mentionned?

Hi evow04,r3wDy
Thank you so much,
The problem has been solved. It's wiring problem (swap between TXD and GND).

nice!

Good luck with it!

I think M8 FE have another serial pins for baseband. TX, RX near jtag pins T139 / T608. GND shared with T136.

Makes sense since we have more then one SOC in the M8
Probably every SOC has its own debug lines.
We should have a baseband SOC, a audio SOC, a WiFi/Bluetooth SOC...

Originally Posted by Loonix

Makes sense since we have more then one SOC

Indeed, every SOC has it´s debug channels, I am sure Meizu added only the Serial port for the CPU & one for the Baseband.

TX, RX near jtag pins T139 / T608. GND shared with T136.

Banxian, did you manage to communicate over this debug port?
And how is the current status on the JTAG ? Did you manage to get it up?

1 VBus
2 D-
3 D+
4 ID (MIC)
5 GND
6 TX
7 ROUT
8 LOUT
9 RX
10 TV-OUT

I make a new defination for M8 USB.

Hi banxian!

this is the pinout for the SE or you remapped the pinout on the FE ???

this pin map works for m9 also. Thanks!

good to hear.
You must have access to the bootloader now I presume?

edit never mention, found your posting