NXP Semiconductors

UM12262

FRDM-IMX91 Board User Manual

MX93AUD-HAT

8MIC-RPI-MX8

Figure 13. Accessory boards

3.2.1 Software configuration update

• To use the MX93AUD-HAT and 8MIC-RPI-MX8 boards together or use the MX93AUD-HAT board alone, run

the following commands at U-Boot to replace the default dtb:

$setenv fdtfile imx91-11x11-frdm-aud-hat.dtb

$saveenv

$boot

• To use the 8MIC-RPI-MX8 board alone, run the following commands at U-Boot to replace the default dtb:

$setenv fdtfile imx91-11x11-frdm-8mic.dtb

$saveenv

$boot

4 PCB information

The FRDM-IMX91 is made with standard 10-layer technology. The material is FR-4, and the PCB stack-up

information is described in Table 22.

Layer

Description

Copper (mil)

Generic

Er

Dielectric thickness (mil)

1

TOP

0.7+Plating

-

-

1.3

-

Dielectric

-

2.61

2

GND02

1.4

-

-

-

-

Dielectric

-

3

3

ART03

1.4

-

-

-

-

Dielectric

-

8.8

4

PWR04

1.4

-

-

-

-

Dielectric

-

4

5

PWR05

1.4

-

-

-

Table 22. FRDM-IMX91 board stack up information

UM12262

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User manual

Rev. 3.0 — 22 April 2025

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