Notice: The ability to use 3.3v ttl level serial is based off of google group discussions and a picture of a serial cable used by an alleged android dev. 2.8v level serial was determined via someone using a voltmeter. Build/use at your own risk and check the comments of this instructable too before beginning!
Information may be applied to build a 2.8v serial to RS232 converter to interact with RS232 devices, or a 2.8v serial to serial 5v level converter to interact with microcontroller such as an Arduino. I may post instructables on how to make these once I play around with the G1 kernel some more. :)
This tutorial assumes basic knowledge of soldering. If you don't have this skill you should find an instructable regarding it and practice a bit. The soldering required for this project isn't difficult, but needs to be done in a small amount of space which could be difficult for beginners.
This cable was created based off of information received from the Android-Platform Google Group.
... Specifically these two threads:
...This picture of a "mystical" g1 serial cable helped (and confused!) too:
Please leave constructive criticism/comments if you find any steps wrong, confusing... or poorly written!
Step 1: Items Needed
- Soldering Iron (Whatever Radioshack/online/etc has should work)
- Solder (Whatever Radioshack/online/etc has in stock that is 0.032 dia. or a little smaller will work)
- Wire Strippers (Don't buy these from Radioshack.. your local hardware shop should have them however)
- Wire cutters
- HTC ExtUSB Breakout board
- 22 AWG solid Wire - It would be best to get red,black and another color of your choice (white) but it is not necessary.
- USB to 2.8V (or 3.3v) serial level converter. It would be best if you could get one that lets you use the 5v line of the USB bus to power the G1, but it is not necessary. Any of the following should work (you only need ONE):
- (Has no 5v line for power) http://www.sparkfun.com/commerce/product_info.php?products_id=8772
- (May be difficult to modify to get 5v line for power) http://www.sparkfun.com/commerce/product_info.php?products_id=718
- (I used this one, has 5v connector) http://www.sparkfun.com/commerce/product_info.php?products_id=198
- (VCC pin should supply 5v... double check however!) http://www.sparkfun.com/commerce/product_info.php?products_id=199
- (This should have a 5v line (VCC).. but there is conflicting information between the store and company specs page) http://apple.clickandbuild.com/cnb/shop/ftdichip?productID=68&op=catalogue-product_info-null&prodCategoryID=47