NXP Semiconductors

UM12262

FRDM-IMX91 Board User Manual

Each Ethernet port has a unique MAC address, which is fused into i.MX 91. The Ethernet connectors are

labeled clearly on the board.

2.15 EXPI connector

One 2x20-pin EXPI connector (P11) is provided on the FRDM-IMX91 board to support I2S, UART, I2C, and

GPIO connections. The header can be used to access various pins or to plug in accessory cards, such as the

LCD display TM050RDH03-41, 8MIC-RPI-MX8 card, and MX93AUD-HAT.

The connector is shown in Figure 3.

Pin number

Net name

Pin number

Net name

1

VRPi_3V3

2

VRPi_5V

3

GPIO_IO02

4

VRPi_5V

5

GPIO_IO03

6

GND

7

GPIO_IO04

8

GPIO_IO14

9

GND

10

GPIO_IO15

11

GPIO_IO17

12

GPIO_IO18

13

GPIO_IO27

14

GND

15

GPIO_IO22

16

GPIO_IO23

17

VRPi_3V3

18

GPIO_IO24

19

GPIO_IO10

20

GND

21

GPIO_IO09

22

GPIO_IO25

23

GPIO_IO11

24

GPIO_IO08

25

GND

26

GPIO_IO07

27

GPIO_IO00

28

GPIO_IO01

29

GPIO_IO05

30

GND

31

GPIO_IO06

32

GPIO_IO12

33

GPIO_IO13

34

GND

35

GPIO_IO19

36

GPIO_IO16

37

GPIO_IO26

38

GPIO_IO20

39

GND

40

GPIO_IO21

Table 20. P11 pin definition

2.16 Debug interface

The FRDM-IMX91 board features two independent debug interfaces.

• Serial wire debug (SWD) header (Section 2.16.1)

• USB-to-dual UART debug port (Section 2.16.2)

2.16.1 SWD interface

The i.MX 91 applications processor has two serial wire debug (SWD) signals on dedicated pins, and those

signals are directly connected to the standard 3-pin 2.54 mm connector P14. The two SWD signals used by the

processor are:

UM12262

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User manual

Rev. 3.0 — 22 April 2025

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