I hate to create another of these threads, but I've plowed through the collected wisdom and am stumped.
I have a new pair of model 1 915mhz radios -- I haven't worked with these before. The ground side plugged into USB fine, green light flashes once a second or so, and I was able to load parameters into the config program on the first try.
The air side is fighting me. It has a connector with black/red/green/bluish. I hooked this up to a Prolific USB<>serial cable red to vcc, black to ground, green to green, white to blue. This appears to be correct.
When the cable is initially plugged in, the green and red leds flash once momentarily. Then nothing (that is, no green led flashing at intervals). Attempts to talk to the command interface with a terminal emulator have so far failed, regardless of baud rate selected. Obviously, I've tried normal commands, +++, etc.
For each character typed, I see the red and green led blink -- seems reasonable. However, there is no echo, no OK, nothing back -- again despite various baud rate settings and reasonable char lengths (needless to say the config program and mission planner aren't doing any better).
I don't had a scope handy, which is a pain. However, a voltmeter attached to the output from the board shows the voltage spike and hold upward if I keep sending characters into the card, suggesting that something is indeed echoing out. And if I connect tx to rx on the prolific usb adapter cable, I see my typed characters echoed appropriately, so that also looks good.
Not making much sense. Any ideas? Thanks!
Replies
Too much words- too few pictures...
Post a picture of connection between air module and USB converter.
If green LED doesn't blink - module is improperly powered or damaged.
I'm looking into the power situation now. Will bypass the cable and go straight to the board. This particular unit has gnd vcc tx rx en c0 // No explicit RTS/CTS, en could be enable, but c0? Also, do these radios usually expect the serial ttl to be idle high or idle low? The cable I have here is idle high. Thanks!
Power it with Vcc nad GND connected only (+5V), rest of pins leave floating.
If you'll have no blinking green LED - there's something wrong with air unit.
If so - try to power up air unit with CTS shorted to GND (this will force bootloader mode and red LED should be solid): https://code.google.com/p/ardupilot-mega/wiki/3DRadio#Forcing_bootl...
If this will work - we will go forward. If not - you have a dead air unit.
Once again - one picture is worth a thousand words...
Major progress. I bypassed the connector and cables completely, and powered from the 5v line of the USB->TTL cable (data logic idle high) straight to the vcc/gnd pads of the card. Card lit up green and few seconds later entered blinking green mode. I haven't tried reconnecting tx rx yet, but I'm assuming idle high will be correct and that will probably work now. I think what was happening was the tx line from the cable (at 3.3v idle) was trying to power up the board (that is, tx was actually connected to vcc) but couldn't really do it. When I entered characters tx kept going to 0v and "blipped" the board so I saw the leds flash each time. My inclination now is to simply bypass the connector and cable and just solder my own leads to the gnc/vcc/tx/rx pads (en and c0 pads are still a mystery, no cts/rts pads are present -- presumably shorting one of c0 or en to gnd would enable bootloader mode if I really needed it). Thanks!
If green is blinking - you won't need this. Try to upgrade FW/configure only with Rx/Tx, rest is not necessary.
Good luck :-)
Thanks again for the assistance!
Much appreciated.