NXP Semiconductors

UM12262

FRDM-IMX91 Board User Manual

2.4 I2C interface

The i.MX 91 processor supports a low-power inter-integrated circuit (I2C) module that supports an efficient

interface to an I2C-bus as a master. The I2C provides a method of communication between a number of

devices available on the FRDM-IMX91 board.

One 10-pin 2x5 2.54 mm connector P12 is provided on the board to support I2C, CAN, and ADC connections.

The developers can use the port for some specific application development.

Table 10 explains the I2C, CAN, and ADC header, P12, pinout.

Pin

Signal name

Description

1

VDD_3V3

3.3 V power supply

2

VDD_5V

5 V power supply

3

ADC_IN0

ADC input channel 0

4

ADC_IN1

ADC input channel 1

5

I3C_INT

I2C/I3C interrupt signal

6

GND

Ground

7

I3C_SCL

I2C/I3C SCL signal

8

CAN_H

CAN transceiver high signal

9

I3C_SDA

I2C/I3C SDA signal

10

CAN_L

CAN transceiver low signal

Table 10. 10-pin 2x5 2.54mm I2C, CAN, and ADC header (P12) pinout

Table 11 describes the I2C devices and their I2C addresses (7-bit) on the board.

Part

identifier

Device

I2C address (7-bit) Port

Speed

Voltage Description

U748

PCAL6408AHK

0x20 (0b'0100000x) MX-I2C1

1 MHz Fm+

3.3 V

I/O expander for IRQ /

OUTPUT

U701

PCA9451AHNY

0x25 (0b'0100101x) MX-I2C2

1 MHz Fm+

3.3 V

PMIC

U725

PCAL6524HEAZ

0x22

(0b'01000[10]x)

MX-I2C2

1 MHz Fm+

3.3 V

IO expander for IRQ/

OUTPUT

U10

FT24C256A

0x50 (0b'1010000x) MX-I2C2

1 MHz Fm+

3.3 V

EEPROM

U705

PTN5110NHQZ

0x52

(0b'10100[10]x)

MX-I2C3

1 MHz Fm+

3.3 V

USB Type-C Power

Delivery PHY

U712

PTN5110NHQZ

0x50

(0b'10100[00]x)

MX-I2C3

1 MHz Fm+

3.3 V

USB Type-C Power

Delivery PHY

U710

NX20P3483UK

0x71

(0b'11100[01]x)

MX-I2C3

1 MHz Fm+

3.3 V

USB load switch

U740

PCF2131

0x 53

(0b'110101[0]x)

MX-I2C3

400 kHz Fm

3.3 V

External RTC

Table 11. I2C devices

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

14 / 34