---
title: "FRDM-IMX91"
description: >-
  The NXP FRDM-IMX91 is powered over USB-C and exposes its console on an
  on-board dual USB-serial bridge, so power and console both run over USB and
  no MIB signals are needed. In our setup, we're making use of a
  [No-MIB](/hardware/mibs/no-mib.md).
---

```{include} common-alert-enablement.md
```

The [FRDM-IMX91](https://www.nxp.com/design/design-center/development-boards-and-designs/FRDM-IMX91)
is powered over USB-C and exposes its console on an on-board dual USB-serial
bridge, so power and console both run over USB and no MIB signals are needed.
DUT can be automated using the [No-MIB](/hardware/mibs/no-mib.md).

This document applies to the following boards:

- FRDM-IMX91: imx91-11x11-frdm

## Components

The following components are required to automate the board:

- [No-MIB](/hardware/mibs/no-mib.md)
- Short RJ45 network cable
- USB-C male to USB-C male cable
- USB-A male to USB-C male cable

![HW modification 1](/_images/frdm-imx91.jpg)

## Hardware modification

None.

```{admonition} Recovery isn't automated
:class: warning
Entering the serial downloader mode requires changing the `SW1` boot mode
switches by hand, so recovery and eMMC reflashing can't be driven automatically.

If automated recovery is needed, solder flying leads across the
`SW1` switches and drive them from the [Flylead MIB](/hardware/mibs/flylead.md)
virtual buttons, as done for the [OSM-IMX93](/devices/osm-imx93.md).
```

### Boot mode switches

Set `SW1[4:1]` to `0010` to boot from the on-board eMMC. This is the factory
default.

## Connections

### Power

Connect a USB C-to-C cable from the LAA [USB port
1](/hardware/peripherals.md#usb-ports) (facing upward) to the FRDM-IMX91 `P1`
USB-C connector. Port 1 is the type-C port with power delivery, and the board
negotiates a USB-PD contract on it.

```shell
laam laacli usb 1 on
laam laacli usb 1 off
```

### Serial

Connect a USB A-to-C cable from the LAA [USB port
2](/hardware/peripherals.md#usb-ports) (facing upward) to the FRDM-IMX91 `P16`
USB-C debug connector.

The Cortex-A55 console is accessible at `/dev/ttyACM0`, served by
[ser2net](/guides/device_type_enablement.md#ser2net-configuration) on port
`2020` at 115200 8N1:

```shell
laam laacli usb 2 on
laam serials connect ttyACM0
```

```{admonition} Leave the console powered
:class: tip
Keep USB port 2 turned on permanently. It only feeds the debug bridge, and
leaving it on keeps the console attached across DUT power cycles.
```

### Network

Connect one of the two on-board RJ45 sockets to the LAA
[private network interface](/hardware/peripherals.md#private-ethernet).