Serial Communication without USB Debug Lead

@ IanW - Looking at your setup you miss gnd cable from pc serial to Cerbuino. So when you detach usb cable you havo no more serial port gnd ref between the two. No ground, no party !
Unless you are using only rx and gnd…

@ dobova - Good catch!

Dear All,

Thanks for all the advice received since I was last online yesterday. The outcomes so far…

andre.m: ‘Active(Debug)’ was previously set under properties, but changing to ‘Release’ does not seemed to have made any difference. Should I use ‘Release’ for this sort of project in future?

Brett: I tried reversing the

UART3.DataReceived += new SerialDataReceivedEventHandler(UART3_DataReceived);

with

UART3.Open();

but no joy here either.

Keith-0: This is a Cerbuino receive-only project, but the laptop seems to be working fine as the USB Xbee Dongle lights flash when an attempt is being made to send data.

Dobova: I have tried connecting a wire between the USB Xbee Dongle Pin 10 (GND) on my laptop and the Cerbuino GND (the one next to Pin13), but this does not seem to have made a difference. Is this the correct way to connect a GND reference or have I connected this incorrectly?

Although not yet working, I sense we are close so I’m keeping optimistic!!!

Many thanks

Ian.

@ IanW - Sorry I’m bit confused … You are using a xbee shield to emulate a TTL rs232 ?
What are you using to send data out from the PC ? I suggest in any case to connect RX-TX-GND wires from cerbuino to the shield. May be there’s some 3.3V to 5V problem on the TTL RS232…

Hi Dobova,

Yes, that’s correct, I am using a USB Xbee Dongle at the laptop end - I have wires running from the DIn on the USB Xbee Dongle to the Cerbuino Di0 and DOut on the USB Xbee Dongle to the Cerbuino Di1 pin (Please see picture above). I am using Tera Term to send out data from the laptop.

Could you please advise on which pins on both the USB Xbee Dongle and Cerbuino which the GND reference wire should be connected?

Many thanks

Ian.

Hi,
I would take GND and the 5 Volt power supply from the USB XBee Dongle to the Cerbuino Bee. You need no additional battery power supply! Where to connect, you can see on both plates at the USB -Plug. Perhaps you have a Volt-meter?
Regards
Roland

PS: GND on the USB XBee Dongle should be on Pin 10 on the connector where you got DIN and DOUT. If you take the 5 Volt direct from the USB-Plug of the XBee dongle it should work.

Hi RoSchmi,

Sucess!!! I connected wiires between the USB Xbee Dongle and the Cerbuino as follows:

USB Xbee Dongle Cerbuino

Pin1 VCC 5V
Pin2 DOUT D1
Pin3 DIN D0
Pin10 GND GND

I am presuming this power supply is safe for the Cerbuiino as the onboard power LED goes slightly dimmer when I disconnect the Debug USB cable.

Many thanks to you and all that have helped with this issue.

Best Wishes

Ian.

Hi,

I dont think that it is correct how you conneted the power supply from the dongle to the Cerbuino Bee. Connection of GND is o.k., but pin 1 of the connector on the dongle is 3.3 Volt. So the voltage regulator of the dongle has to feed the Cerbuino Bee. I dont know, whether it is strong enough. I would solder a connection from the 5 Volt from the USB Connector from the dongle to the corresponding pin of the USB Connector on the Cerbuino Bee.

But be careful: Never never never connect the 5 Volt from the dongle to a Pin on the Cerbuino Bee where VCC = 3.3 Volt are expected. That would kill the Cerbuino Bee at once.

All on your own risk! And… I would be careful and not connect two different PCs to the “assembly”.

Regards
Roland

Hi RoSchmi,

I have checked the voltage at Pin1 of the XBee USB Dongle and it is 3.41 volts. Connected to the Cerbuino’s 5 volt socket, it seems to work fine. However, when I tried this with my Domino, I had to also use additional battery power for it. With the support of a battery, the Domino could also read the serial communications from the Dongle when the Debug USB was disconnected.

I will avoid plugging anything above 3.3 volts into the 3.3 volt socket on either the Cerbuino or Domino though as you have suggested as that might prove rather expensive!

Regards

Ian.