No COM port after flashing

Wireless & IoT LoRa (Long Range)
1

Issue: My WRL-14916 no longer gets an assigned COM Port after I flashed it with an enlarged program.

Question: How can I recover this WRL-14916 unit’s ability to get an assigned COM Port when I plug it into the PC?

Specifics:

  • WINDOWS 10 machine

  • ARDUINO IDE is version 1.8.12

  • Connection is between PC USB and WRL-14916 micro-B USB

  • The RED LED of the WRL-14916 is lit as normal

  • IMPORTANT → (Using the same cable) a brand new WRL-14916 gets an assigned COM Port listed as “COM17 Sparkfun SAMD21 Pro RF” by ARDUINO IDE (and Device Manager shows both COM1 and COM17 being active) but the original WRL continues to show only COM1 (and Device Manager shows only COM1 being active)

Other Observations:

  • The program that originally, successfuly uploaded onto the WRL-14916 was the Adafruit_TSL2591 example “tsl2591”

  • That program had no compile erors and uploaded but the expected Serial Monitor printouts were blank (no activity)

  • That Serial Monitor shows up on COM15 port (only port listed) but I notice this readout from the compilation messaging:

Forcing reset using 1200bps open/close on port COM15

PORTS {COM1, COM15, } / {COM1, } => {}

PORTS {COM1, } / {COM1, COM9, } => {COM9, }

Found upload port: COM9

  • For debugging I added code to light-up LEDS as the WRL-14916 progressed through the “tsl2591” example and it did progress BUT it never showed anything on the Serial Monitor when it progressed through a “Serial.print”

  • Eventually after additional debugging no COM PORT was being assigned to the WRL-14916

HOW DO I ENABLE THE ORIGINAL WRL-14916 TO GET AN ASSIGNED COM PORT?

2

Sometimes something in your code will cause the microcontroller to hang or get stuck in a loop.

Try double clicking the reset button. That should drop the board into bootloader mode and give you a COM port that way. Keep in mind the COM port number will probably change from what you were originally using.

3

SOLVED!

As TS-CHRIS suggested, I double clicked the RESET button of the connected WRL-14196 and suddenly Port COM9 was assigned it. Now I can download programs to it. THANKS!