NXP Semiconductors

UM12262

FRDM-IMX91 Board User Manual

Part identifier

Connector type

Description

Reference section

P15

3.5 mm headphone jack

MQS connector

Section 2.6

P17

USB 2.0 Type A

USB connector

Section 2.13

P18

JST_SH_2P

RTC battery connector

For detail, see the board schematic

Table 3. FRDM-IMX91 connectors...continued

1.6 Push buttons

Figure 4 shows the push buttons available on the board.

Table 4 describes the push buttons available on FRDM-IMX91.

Part identifier

Switch name

Description

K1

Power button

The i.MX 91 applications processor supports the use of

a button input signal to request main SoC power state

changes (that is, ON or OFF) from the PMIC.

The ON/OFF button is connected to the ONOFF pin of the

i.MX 91 processor.

• In the ON state:

– If the ON/OFF button is held longer than the debounce

time, the power off interrupt is generated.

– If the button is held longer than the defined max timeout

(approx. 5 s), the state will transit from ON to OFF, and

send PMIC_ON_ REQ signal to turn off the powers of

PMIC.

• In the OFF state:

– If the ON/OFF button is held longer than the OFF-to-

ON time, the state will transit from OFF to ON, and send

PMIC_ON_REQ signal to turn on the powers of PMIC.

K2

User button

The User button is kept for customized use cases.

K3

Reset / User button

By default, K3 is connected with SYS_nRST and used as a

reset function. To use K3 as a customized function, remove

the R3061 resistor and install the R2612 resistor.

Table 4. FRDM-IMX91 push buttons

1.7 DIP switch

The following DIP switches are used on the FRDM-IMX91 board.

• 4-bit DIP switch – SW1

• 2-bit DIP switch – SW3

• 1-bit DIP switch – SW4

If a DIP switch pin is:

• OFF – pin value is 0

• ON – pin value is 1

The following list describes the description and configuration of the DIP switches available on the board.

UM12262

All information provided in this document is subject to legal disclaimers.

© 2025 NXP B.V. All rights reserved.

User manual

Rev. 3.0 — 22 April 2025

Document feedback

8 / 34