Receiving Data from a Client

I have been trying to understand the coding needed to use the Notecards for my simple MQTT project. As TJ suggested, I trimmed down the “Collecting Sensor Data” program (on the Swan) to send data from the notecard through CloudMqtt to my cellphone as a client using the “MQTTAnalyzer” app. This has been working fine, but now I want to send data to the notecard from my cellphone through CloudMqtt.
After numerous hours of researching and trying different options, I came across an example file in the Arduino IDE for Blues notecard called “Example 4_InboundInterrupts”. I have a WBNAW NoteCard on a NoteCarrier-F. I downloaded the example onto a UNO R3 and set D5 as an input to connect to the NoteCard’s “N_ATTN” pin and put in the Product ID. The example does not explain the serial wiring and possible switch positions on the NoteCarrier.
Is the NoteCard’s TxRxPins Serial 9600 baud?
Does the NoteCard’s “AUX” switch need to be in DFU or Normal?
Does the “Feather_EN” switch position matter? (I removed the SWAN from the NoteCard)
If I have the RX wired to TX, and TX wired to RX with a ground, it looks like the serial connection is connected to the USB on the UNO because I have to remove the TX/RX wiring to download the program to the UNO. Even with the USB unplugged the N_ATTN pin does not change states when I send a message to the NoteCard. Any simple beginner level suggestions would be appreciated. Thanks

Hi @DonL,

I’d love to see a picture of what you’ve got going on, so I’m sure I’m giving you good advice.

Is the NoteCard’s TxRxPins Serial 9600 baud?


Does the NoteCard’s “AUX” switch need to be in DFU or Normal?


Does the “Feather_EN” switch position matter?

Yes. This binds the Notecard’s ATTN pin to a multiplexor that switches off power to the Feather and Qwiic connectors. Since you are using the ATTN pin for a signal, then you will want to switch Feather PWR to “ON”, instead of “switched”.

Finally, a picture is worth a thousand words, so if you can share a pic of your setup, it will make it easier for us to help.