I am using FTDI connector to program my whisper nodes.

When I swap one whisper board with the other and try to upload a sketch through the Arduino IDE, I am having the avrdude not in sync error. I am using the DTR -- DTR, Tx- Rx, Rx-Tx, VCU-VIN, GND-GND from FTDI to Whisper Node.

Interestingly one Whisper Node worked with 3.3 V input while the other did not with this, but when changed to 5 V on FTDI it worked.

Now when I swap or change the boards to program as Base and Node I am having avrdude not in syn error. I am using CDM v.2.08.28 Certified driver for FTDI connector. COM port is all correct.

Appreciate any help, having hard time with this avrdude.

I’ve had the same issue occasionally. Disconnecting the ftdi and reconnecting seems to work for me. Seems like the ftdi fails to acknowledge the device. Closing the Arduino Programmer and restarting also should reset.

thank you for your reply. 

I have tried disconnecting FTDI and reconnecting, restarting the IDE and also uninstalling the USB serial converter. The issue is only for swapping. I can still program one of the whisper boards any number of times no problem.

I am not able to switch to other board with the FTDI connector. I measured the Volts on DTR on the whisper board , it is about 4.96 V (close to 5 V ) and then it drops to 0 or slightly negative at the time of the Upload for a second and almost spikes back to 4.96V, VIN volts about 5 V, RX it is close 4.93 or so and Tx about 3.24. The same voltages are observed on the FTDI connector.

Somewhere I saw that the DTR voltage need to come back slowly allowing time for Whisper Node chip to realize new upload is coming through, but I do not think that is issue ? The connector works with one board just fine. 

What exactly is happening when 
1. FTDI is disconnected and reconnected?
2. When the Arduino IDE is restarted ?

Hi nashdwaj,

Make sure your FTDI is supplying more than 3.4V (5V is OK) to the Whisper Node VIN pins (which include the FTDI).

Apart from that I have some problems from time to time where the FTDI adapter simply restarts and I can hear the sound (Windows sound) of an USB device being disconnected from the PC. I need to disconnect and re-connect the FTDI, but that happens not only with the Whisper Node and seems to be an issue with the FTDI adapters itself - maybe when connecting to a device a spike of current cause the FTDI to fail? (just guessing)

Anyway, to minimize this problem I normally have a few FTDIs (as they cost very little at eBay)... I also, sometimes, power the boards directly via the micro-USB and connect all pins but VCC from the FTDI adapter.

Glad it isn't just me on this one.