You have TX connected to TX? Swap your TX/RX connections and see if the levels improve.
Tom Harris <celephi...@gmail.com> On 3 June 2015 at 14:38, Dan Quigley <d...@quigleys.us> wrote: > Hello, > > I'm integrating an Arduino (Due/Mega have tried both) with a surplus > Thunderbolt and need some advice. > > The Thunderbolt is a known working unit (supplies 10Mhz to my HPSDR rig) > and the serial interface works fine between it and a PC. I've read the > coverage about this kind of integration (and some of the archived > discussions on this board) and am employing a commercially available > MAX232-based "shield" (RS232 V2) to handle the level translations. Just > three lines (RX/TX/GND) are used. The MAX232 circuit is working, reliably > passing data between the Arduino and a PC. > > With the Thunderbolt is connected to the MAX232 no data passes. Activity > LEDs on the non-RS232 of the MAX232 circuit show no activity when the > Thunderbolt is providing data, indicating the MAX232 is not performing the > intended level translation. I've scoped the RX/TX lines coming from the > Thunderbolt both when connected to the Arduino and not. There is a > distinct difference. When disconnected, the pulses are about 10.3v and > nice, crisp and square. Connected, the pulses are ~50% lower in voltage > (4.1v) showing an exponential rise in voltage and trace noise. > > I'm pretty much stumped at the moment and wonder if anyone can offer a > suggestion or thoughts on a direction to take. > > Thanks in advance, > Dan Quigley (N7HQ) > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.