Lost Comm with Cell Tower

Everything was working fine yesterday…

Today I can’t communicate with the cell tower. Here’s some trace information:

type or p{"req":"card.trace","trace":"+req,mdm,mdmmax,comm,sync", "mode":"on"}

R05:44.30 i2c3: state auto-reset by timer

S10:06.14 sync: connect requested by need imei/imsi/iccid (TRANSPORT)

S10:06.15 apn: for a.notefile.net using apn a-notehub.com.attz

S10:06.16 sync: wireless: domain a.notefile.net using APN a-notehub.com.attz

S10:06.16    339 < PowerOn

S10:06.17 modem: 4.80V 26.38C at power-on

S10:06.17 sync: wireless: starting communications {wait-module} {connecting}

M10:06.17 modem: watchdog poll interval changed from 900000ms to 750ms

S10:10.25 sync: wireless: modem now ON {modem-on}

M10:11.40      5 < PostReset            RDY

M10:11.40      5 > EchoOff              ate0

R10:11.41 i2c3: state auto-reset by timer

S10:12.66 sync-task: change polling from 300000ms to 750ms for high responsiveness

M10:14.92      8 < EchoOff              APP RDY

R10:14.93 i2c3: state auto-reset by timer

M10:31.81     25 < Heartbeat

M10:33.35 *** MODEM TRANSACTION TOO LONG EchoOff ate0 (20 sec)

M10:33.35 _log.qo: *** MODEM HARD RESET EchoOff ate0 (20 sec)

aste code here

It just keeps resetting the module. This happened once before, and it worked the next day (connected to Notenub and sent up notes).

The above trace is with the Notecard usb powered.

What happened?
What else can I check?

@mdf possibly irrelevant… but I’ve had issues way back with the notecard powered over usb on an older laptop and also on a multi-port adapter – resets. With new laptop and full-size computer no problem.

It’s working again today. Here’s the session info:

    "event": "41072e2f-887f-4a40-b63a-9e5c79da9986",
    "session": "261563a8-879e-4b19-b663-4414f0f971b0",
    "device": "dev:864622040372605",
    "product": "product:XXXXXXXXXXXXXX",
    "received": 1623255271.417952,
    "routed": 1623255273,
    "req": "session.begin",
    "when": 1623255271,
    "file": "_session.qo",
    "body": {
        "why": "1 file(s) requested sync (sensors.qo)"
    "tower_when": 1623255271,
    "tower_lat": XXXXXXXX,
    "tower_lon": XXXXXXXX,
    "tower_country": "US",
    "tower_location": "Raleigh, North Carolina",
    "tower_timezone": "America/New_York",
    "tower_id": "310,410,10000,197103889",
    "moved": 1623254583,
    "orientation": "face-up",
    "rssi": -67,
    "sinr": 146,
    "rsrp": -92,
    "rsrq": -10,
    "rat": "emtc",
    "bars": 2,
    "voltage": 4.78,
    "temp": 29.81,
    "reply": "https://api.notefile.net/req?product=\"product:XXXXXXXXXXXXXXXX\"&device=\"dev:864622040372605\""

The cell tower is not far. Does the connection look weak?

Are there limitations on data usage with this SIM? I’m developing, and testing DFU in particular, so am using more data than would be normal.

Hey @mdf, based on the rssi in your session info, the connection looks fine. If you lose the connection again, please hit us up directly at support@blues.com or via the help widget in Notehub so we can view the live trace and help troubleshoot the issue.

As for data usage limitations, there are no monthly or periodic limitations for using the 500MB baked into the Notecard, so you can absolutely use more data during active development than you would in a deployed product and it will work just fine.

So, I lost comm again today. But got it back later by removing the batteries, (disabling the MCU) and connecting to a PC over USB.

I am using the Note Carrier-AA, and using the BAT output to supply my MCU (nrf52840). The battery voltage is now down to 3.86V. If it’s not communicating (or just to debug) then I connect the USB port on the Note Carrier to my PC to check out the debug info. The batteries remain in, since they are supplying the power for the MCU.

Is this arrangement a problem?
What is the lowest voltage (AA batteries, Energizer MAX alkaline) that will work reliably for battery only operation?