Following on from this thread:
I made a serial cable for the ADP1 and thought it would be good to
record how publicly. Thanks to the posters on that thread for
indicating that it is possible.
| A B C D E |
\1 2 3 4 5 6|
3: Switch / Rx / CABLE_IN2
4: GND / Tx / CABLE_IN1
I.E. this is the same diagram as the one at http://www.tracyandmatt.co.uk/blogs/index.php/2006/09/10/htc_hermes_usb_connector_pin_config
, with Rx and Tx labelled. Pins A-E are USB, and pins 1-6 are headset
(if pin 4 is connected to pin A) or serial (otherwise). These pins are
referred to as CABLE_IN1 and CABLE_IN2 in the Linux source code (arch/
This isn't standard RS232, so don't hook it directly to an RS232 port!
It looks like serial is at cmos ttl levels (~2.8 volts) so you will
need to make sure you are communicating at that level. Sparkfun also
sells an adjustable-voltage ttl-serial converter which worked for me.
The port runs at 115200bps, 8N1.
It should be straightforward to make a dual USB / serial cable, but I
haven't done this yet.
Hope somebody else can make use of this. :)
Yep, there doesn't seem to be much out there! Glad you found this
> I used a cp2102 and have been taking pictures for a
> pictorial.. I'll throw it up on instructables.com when I am done. If
> there is interest here, I'll post a link.. just let me know.
Sounds good to me.
> Something I have observed... are you sure you don't have the rx/tx
> flipped about? Mine works, but I think I had to flip them.. It is a
> little confusing to convert from the podgizmo chart to the other one
> however so I could be mistaken.
Hmm, I think you might be right. There is a post in the comments
section of that product page about "uart dyslexia" and I can
> For the ttl-serial converter you got from sparkfun (http://
> www.sparkfun.com/commerce/product_info.php?products_id=449) what
> extusb pin are you using to feed vcc 2.8v?
I couldn't find a pin that supplied +2.8v so I used my own power
supply. I've decided the easiest thing to do is use the +5v supplied
from the host computer combined with an lm317 circuit to drop the
voltage to 2.8v. Seems to work. Possibly I don't need to be this
paranoid, but I don't want to risk my phone! If you come up with
something neater, though, I'd be keen to hear about it.