Unable to perform 2 way comms with ATMEGA168A-AU using FT232RL

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1

Hello,
I have been unable to perform 2 way comms with a PCB I developed 2 years ago, using the ATMEGA168A-AU micro with an FT232RL serial chip, connected exactly like the Arduino. I had no problems using this board with this chip until recently, when it stopped allowing me to upload programs. I have tried all of the following to make it work with no success: swapping the PCB with a known good, swapping the micro/ft232RL/crystal, utilized different USB cables, utilized different computers with both win 7 AND xp, and utilized older versions of Arduino. The chip will bootload fine with the WinAVR MKII programmer AND the USBTINY programmer from Ladyada, and can be programmed with code using these programmers. The crystal frequency is 16.0000 Mhz according to my recently calibrated scope, and VCC is at 5.004V. Loading a program that simply sends data out on the serial to usb chip works, I was able to see data streaming in to the computer in the Arduino IDE, however sending a command over USB to the chip results in no output (confirmed good data in and no data out to the micro using my scope). As a side note, I tried using my Arduino Duemilanove PCB and had no problems with 2 way comms. As I said, in past this board worked perfectly, I have not changed a thing on it. I am all out of ideas, help??

2

Are you saying that your "Arduino" can send text to Serial Monitor and you can use your scope to see text from Serial Monitor arriving at the receive (RX) pin of your "Arduino" but the "Arduino" sketch does not respond to the received data? And that the same sketch running on a genuine Arduino does respond?

3

johnwasser:
Are you saying that your "Arduino" can send text to Serial Monitor and you can use your scope to see text from Serial Monitor arriving at the receive (RX) pin of your "Arduino" but the "Arduino" sketch does not respond to the received data? And that the same sketch running on a genuine Arduino does respond?

Yes, exactly. The only difference is my "Arduino" uses an SMT atmega168a-au running at 16Mhz, like the arduino nano. I always was able to program it in the past by selecting the board "Arduino pro or pro mini (5V, 16 MHz) w/ ATmega168".

4

Okay, built up a whole new PCB and it worked fine. I can't explain this one...