Can’t use serial between Adafruit Feather M0 Adalogger and NOTECARRIER-F V1.0


I’m using an Adafruit Feather M0 Adalogger on my NOTECARRIER-F V1.0. Currently, I’m using a very simple code based on the examples but can’t make a serial connection to send the data to the blues notehub. When I’m using the I2C interface, everything is working and I can see the data in the notehub. However, when I’m using the serial by uncommenting the line “#define txRxPinsSerial Serial1” I get “notecard not responding” in the ArduinoIDE serial and no data in the notehub. I feel like I’m missing something basic, but not sure what it is.

Thank you,

#include <Notecard.h>

#define txRxPinsSerial Serial1
#define usbSerial Serial

#define PRODUCT_UID “…” //in the code I uploaded, I inserted my UID - it worked with I2C communication but not with serial

#define myProductID PRODUCT_UID
Notecard notecard;

void setup()
// Set up for debug output (if available).
#ifdef usbSerial
// If you open Arduino’s serial terminal window, you’ll be able to watch
// JSON objects being transferred to and from the Notecard for each request.
const size_t usb_timeout_ms = 3000;
for (const size_t start_ms = millis(); !usbSerial && (millis() - start_ms) < usb_timeout_ms;)

// Initialize the physical I/O channel to the Notecard

#ifdef txRxPinsSerial
notecard.begin(txRxPinsSerial, 9600);

// "newRequest()" uses the bundled "J" json package to allocate a "req",
// which is a JSON object for the request to which we will then add Request
// arguments.  The function allocates a "req" request structure using
// malloc() and initializes its "req" field with the type of request.
J *req = notecard.newRequest("hub.set");

// This command (required) causes the data to be delivered to the Project
// on that has claimed this Product ID (see above).
if (myProductID[0])
    JAddStringToObject(req, "product", myProductID);

// This command determines how often the Notecard connects to the service.
// If "continuous", the Notecard immediately establishes a session with the
// service at, and keeps it active continuously. Due to the power
// requirements of a continuous connection, a battery powered device would
// instead only sample its sensors occasionally, and would only upload to
// the service on a "periodic" basis.
JAddStringToObject(req, "mode", "continuous");

// Issue the request, telling the Notecard how and how often to access the
// service.
// This results in a JSON message to Notecard formatted like:
//     {
//       "req"     : "service.set",
//       "product" : myProductID,
//       "mode"    : "continuous"
//     }
// Note that `notecard.sendRequestWithRetry()` always frees the request data
// structure, and it returns "true" if success or "false" if there is any
// failure. It is important to use `sendRequestWithRetry()` on the first
// message from the MCU to the Notecard, because there will always be a
// hardware race condition on cold boot and the Notecard must be ready to
// receive and process the message.
notecard.sendRequestWithRetry(req, 5); // 5 seconds


void loop()

// Count the simulated measurements that we send to the cloud, and stop the
// demo before long.
static unsigned eventCounter = 0;
if (++eventCounter > 25)

// Rather than simulating a temperature reading, use a Notecard request to
// read the temp from the Notecard's built-in temperature sensor. We use
// `requestAndResponse()` to indicate that we would like to examine the
// response of the transaction.  This method takes a JSON data structure,
// "request" as input, then processes it and returns a JSON data structure,
// "response", with the response. Note that because the Notecard library
// uses malloc(), developers must always check for `NULL` to ensure that
// there was enough memory available on the microcontroller to satisfy the
// allocation request.
double temperature = 0;
J *rsp = notecard.requestAndResponse(notecard.newRequest("card.temp"));
if (rsp != NULL)
    temperature = JGetNumber(rsp, "value");

// Do the same to retrieve the voltage that is detected by the Notecard on
// its `V+` pin.
double voltage = 0;
rsp = notecard.requestAndResponse(notecard.newRequest("card.voltage"));
if (rsp != NULL)
    voltage = JGetNumber(rsp, "value");

// Enqueue the measurement to the Notecard for transmission to the Notehub,
// adding the "sync" flag for demonstration purposes to upload the data
// instantaneously. If you are looking at this on you will see
// the data appearing 'live'.
J *req = notecard.newRequest("note.add");
if (req != NULL)
    JAddBoolToObject(req, "sync", true);
    J *body = JAddObjectToObject(req, "body");
    if (body != NULL)
        JAddNumberToObject(body, "temp", temperature);
        JAddNumberToObject(body, "voltage", voltage);
        JAddNumberToObject(body, "count", eventCounter);

// Delay between samples
delay(15 * 1000); // 15 seconds


Hi @Elad and welcome to the Blues community!

When connecting over serial on the Notecarrier-F, you want to make sure the DFU dip switch is toggled to “OFF”. This is because “ON” allows you to use Notecard Outboard Firmware Update, but doesn’t let you connect to the Notecard over serial.

Hope that helps!

1 Like

Hi Rob,

Great, I toggled the DFU dip switch to “OFF” and now it’s working perfectly.

Thank you for the fast answer.