SparkFun Simultaneous RFID Tag Reader + Particle Boron connection

Development Boards Other Microcontrollers
1

Hi,

I am trying to hookup SparkFun Simultaneous RFID Tag Reader (SRTR) with Particle Boron board. So far, I have successfully ‘ported’ the provided Arduino library code to the particle build environment and the code seems to compile and run correctly. I am using the “Hardware Serial Constant Read” example. Now, when I try to communicate with the SRTR via Boron, I am getting “Incomplete response” message.

Upon further debugging, I realized that my HW connection may not be correct. I powered the SRTR via Li-Po 3.7 battery. The red LED on the board is ON. I have put the board in HW-UART position via the dip-switch and have connected the RX/TX lines (right next to the dip-switch i.e. lower right corner of the board, i.e. close to the internal antenna) to the RX/TX lines on the Particle Boron. At this point I am thinking that I do not have a common ground causing the 2 boards to have the different voltage levels and hence my communication is messed up.

Now, which pin on the SRTR board I can use to have a common ground with the particle Boron. There is a ground

pin on the Particle IC.

Any feedback is appreciated. If there are any other suggestions, please let me know as well.

Thanks for your time,

SYED

2

Hello SYED,

You can find a pinout [here. The ground pin looks to be on the long header, 4 pins away from the USB connector, it should be labled with GND.

If that doesn’t fix your problem, it looks like the error message indicates that there is a possible message timeout. https://github.com/sparkfun/SparkFun_Si … r.cpp#L789](https://docs.particle.io/assets/images/boron/boron-pinout-v1.0.pdf)

3

Hi Brandon,

Thanks for the reply. Yes, I understand the GND pin on the Boron. I did try to connect that pin to couple of GND pins on the SRTR but not sure which one to pick. Looks like there are at least 5 GND pins on SRTR :slight_smile:

Also, I disconnected the TX/RX lines completely and the error message turned to “Time out 1: No response from module” which indicates that the SRTR is communicating when the TX/RX lines are connected but something is off and hence the message shows “Time out 2: Incomplete response”.

I’ll keep digging but if there are any further suggestions please let me know.

Thanks,

SYED

4

You can connect to either of the 5 GND pins. They are all connected to each other. I think your issue is 3.7V power supply only. This power supply is feeding (through a diode) the VCC. Thus of the 3.7V only 3V is left (at best). The board has a level shifter that will convert the signals between VCC the on-board generated 3V3. I advice you to connect 5V to the VCC of the serial connector and leave use the 3.7V as power support. Be awarre that the NANO module is very sensative to good power supply.