ANT Forum

Hi,

I am trying to connect a C782M5IB module to an Arduino using a battery board. I have previously connected a similar module to an Arduino directly, which is working fine. But, I don't seem to be able to get it working using the battery board.

My dip switch settings (for 9600 baud rate):
IOSEL - VCC
PORTSEL - GND
BR1 - VCC
BR2 - GND
BR3 - VCC

I just connected power, ground, Rx and Tx to the Arduino. I have not connected the RTS pin - I didn't do this with the module I connected directly and this is working fine.

Any ideas what I might be doing wrong?
Thanks,
Mark      

Hi,

Is the power for your radio being driven by the Arduino or the battery? If VCC is hooked from the Arduino directly to the battery board, Arduino provides higher voltage than the battery so there would be back current to the battery.

If the battery is providing power to the radio separate from the Arduino board, then there needs to be voltage level shifting between the battery board and Arduino as they operate at different voltages.

RTS provides flow control for the UART interface so it's a bit surprising to see proper communication working without it.

Cheers,
Harrison      

Hi Harrison,

thanks for your quick response!

I am powering the radio of the Arduino's 3.3V power supply. I have no battery inserted.

RTS provides flow control for the UART interface so it's a bit surprising to see proper communication working without it.
I am absolutely no serial expert, but I interpreted the ANT documentation as if the RTS only indicates when the radio is ready to receive (Interfacing with ANT General Purpose Chipsets and Modules, page 8). I am using the radio as a receiver, so the only data I send from the Arduino to the radio is the configuration commands. I included a short pause between the various configuration commands to work around the RTS. Is this supposed to work? (It is working for the radio that I connected directly).) If this is not supposed to work, can you provide a little more info on using the RTS pin.

For the radio I connected directly I tied all pins that have to do with EEPROM to ground, as I am not using this. Since the documentation states that those pins can be left unconnected, I did not bother connecting these pins for the radio that I am trying to connect using the battery board. (I only connected power, ground, rx, tx). Can this be causing the one board to work and the other not?

Thanks again,
Mark      

Hi Mark,

Here's a couple questions/suggestions:

Arduino boards come in two voltage flavours (3.3V and 5V). If you are using a 5V Arduino you will have to use level shifting otherwise there could be unreliable communication/damage on the I/O lines.

It is strongly recommended to implement the RTS line. Without an RTS connection you will also be unable to determine if the ANT chip has been reset reliably, although since you do have an implementation working without the battery board are you reading back the confirmation messages from the ANT chip to confirm your configuration messages are going through correctly?

The 20 pinouts on the battery board do not directly correlate to the 20 pinouts on the molex connector for the C7 module, are you following the battery board pin out found in the ANT Development Kit User Manual here? It's recommended to follow TI's sample designs as closely as possible.

A timing diagram would be useful to see if the microcontroller and ANT are communicating properly.

Cheers,
Harrison