NXP Semiconductors

UM12262

FRDM-IMX91 Board User Manual

• SW1 – Provides control for boot mode configuration. For detail, see Section 2.5.

• SW3 – Provides control for enabling or disabling the CAN interface signals, CAN_TXD (GPIO_IO25) and

CAN_RXD (GPIO_IO27), on the board.

Switch

Signal

Description

SW3[1]

CAN_TXD (GPIO_IO25)

– ON (default setting): Enables CAN_TXD signal

– OFF: Disables CAN_TXD signal

SW3[2]

CAN_RXD (GPIO_IO27)

– ON (default setting): Enables CAN_RXD signal

– OFF: Disables CAN_RXD signal

Table 5. SW3 configuration

• SW4 – Provides control for enabling or disabling the CAN split termination RC filter.

Switch

Signal

Description

SW4[1]

– ON (default setting): Enables RC termination filter (62 Ω + 56

pF) and configures CAN bus for normal operation.

– OFF: Disables RC termination filter for test mode.

Table 6. SW4 configuration

1.8 LEDs

The FRDM-IMX91 board has light-emitting diodes (LEDs) to monitor system functions, such as power-on and

board faults. The information collected from LEDs can be used for debugging purposes.

Figure 4 shows the LEDs available on the board.

Table 7 describes the FRDM-IMX91 LEDs.

Part identifier

LED color

LED name

Description (When LED is ON)

D601

Red

PWR LED

Indicates 3.3 V power-on status. When 3.3 V is available

on board, the D601 LED turns ON.

LED1

Red / Green / Blue

RGB_LED

User application LEDs. Each of these LEDs can be

controlled through a user application.

• Red LED connects to target MPU pin GPIO_IO13

• Green LED connects to target MPU pin GPIO_IO04

• Blue LED connects to target MPU pin GPIO_IO12

D613

GREEN

LED_GREEN

D613 ON – WLAN status indicator. When ON, indicates

that the WLAN connection is established.

D614

ORANGE

LED_ORANGE

D614 ON – Bluetooth status indicator. When ON, indicates

that the Bluetooth connection is established.

Table 7. FRDM-IMX91 LEDs

2 FRDM-IMX91 functional description

This chapter describes the features and functions of the FRDM-IMX91 board.

Note: For details of the i.MX 91 MPU features, see i.MX 91 Applications Processor Reference Manual.

The chapter is divided into the following sections:

• Section "Processor"

• Section "Power supply"

UM12262

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User manual

Rev. 3.0 — 22 April 2025

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