nRF93M1 DK: Modem bypass

This sample configures the modem UART switch in bypass mode, forwarding it to the USB CDC-ACM VCOM port. This allows a host PC can send AT commands directly to the modem.

Requirements

The sample supports the following development kit:

Hardware platforms

PCA

Board name

Board target

nRF93M1 DK

nrf93m1dk

nrf93m1dk/nrf54l15/cpuapp

Overview

The sample configures the nRF54L15 host core to directly route the modem serial UART to the USB virtual COM port. It also handles modem power sequencing on startup using a deferred work item.

The following GPIOs are exposed through the buttons on the development kit:

  • Button 1 - Triggers the POWER_KEY signal to the modem.

  • Button 2 - Triggers the RESET signal to the modem.

The UART baud rate is 115200.

Building and running

This sample can be found under samples/nrf93m1dk/modem_bypass in the nRF Connect SDK folder structure.

To build the sample, follow the instructions in Building an application for your preferred building environment. See also Programming an application for programming steps and Testing and optimization for general information about testing and debugging in the nRF Connect SDK.

Note

When building repository applications in the SDK repositories, building with sysbuild is enabled by default. If you work with out-of-tree freestanding applications, you need to manually pass the --sysbuild parameter to every build command or configure west to always use it.

Testing

After programming the sample to the development kit, complete the following steps:

  1. Connect the kit to the host PC using a USB cable. The kit enumerates as a USB CDC-ACM serial port.

  2. Open a serial terminal (for example, nRF Connect Serial Terminal) at 115200 baud.

  3. Send an AT command, for example, AT, and verify that the modem responds with OK.

  4. Press Button 1 briefly to trigger the modem POWER_KEY signal.

  5. Press Button 2 to trigger the modem reset signal.