Thursday, June 4, 2009

Lessons learned 2

This is how the board looks after it was populated.


The main reason for the hack was to install a connector to Tx/Rx pins of the microcontroller. So, always wire Rx/Tx pins of the microcontroller to an external connector (e.g. FTDI) that you can use for serial communication. Otherwise, your software issue (sketch fix/upgrade) becomes hardware.

(to be continued)

2 comments:

  1. I just made a similar mod to the board you sent me! I drilled 4 small holes and epoxied in a 4 pin sip for +, gnd, Rx, & Tx. (I use an LED on the Rx line to tell me when to press reset so that's all I need.) I assume the transistor you have is to reset automatically? I can now load the board directly which is nice at my current stage in development!
    Cheers!
    BroHogan

    ReplyDelete
  2. The transistor is supposed to drive the reset line to ground, based on a signal from XBee. There are 2 documented methods that I know: one described by Rob Faludi (output pin from atmega drives the reset, "rejected" by ATMEL), the other described by ladyada (pin D3 from XBee drives atmega's reset). I will write some conclusions later, since I am working on the second method (first one did not work for me).

    ReplyDelete