Unable to get UART1 output

Q&A forumCategory: QuestionsUnable to get UART1 output
geom asked 3 weeks ago

I’m strugling since a few nights to get a simple UART1 output over BT. I’ve tried an read a lot, but with no result.
My simpleRTK2B came a week ago and I did a firmware update from 1.00 to 1.10, which wasn’t successfull the first time, but finally worked.
I can connect over usb to u-center and using the NTRIP client I get under not ideal conditions (Ardusimple antenna is indoor close to a window)  a 3D/DGNSS/FLOAT.
I want to use the F9P with an Bt connection and I use a HC-05 (configured as SLAVE, Baud 115200). In u-center I ajusted the baudrate for UART1 also to 115200. The HC-05 is connected directly to the 5V/GnD pins on the board and the RX/TX is cross connected to the RX1/TX1 pins of the board. I followed the instructions described here and I checked my configuration over and over. I changed the HC-05 module with another HC-05 I’m using with a M8T board without issues. I changed the wires and readed again whatever I could find about F9P, bluetooth, HC-05,… no chance.
I tried to reset the board to default and I used the rover configuration file (for 1.10 here from the forum). I’ve tried differnt UART1 outputs (UBX, NMEA, RTCM3) without any result.
Whatever App I’ve tried after pairing the BT-module without issues to my tablet (LEFEBURE, Bluetooth GPS Provider, GNSS Commander, MapitGIS NTRIP-client, RTKGPS, Bluetooth viewer, DSD tech bluetooth with HC-10) I get no messages at all? The same when i try to use the module as GPS provider over BT in QGis on Macbook pro.
Since things start to become really boring I must consider the possibility that the board is broken or at least the UART1?
If someone has an idea what I could do or how to check if UART1 is really dead, I would really apreciate it.
Otherwise I’ll see no other solution than sending the board back to Ardusimple.
But I still hope. 

Ardusimple Staff replied 3 weeks ago

You need to provide at IOREF the voltage that you want at UART1. If you want 3.3V UART, you need to connect IOREF to 3.3V. Let us know if this solves the connection.

geom replied 3 weeks ago

THAT’s it! It was so (ardu)simple, and I’ve even remarked now, that You mentioned that in your hookup guide. I connected the IOREF to the 5Vpin of the board.
So thanks for Your reply. I hope that others, who encountered similar problems my find this solution.