NXP Semiconductors

UM12262

FRDM-IMX91 Board User Manual

Figure 10. Resistors configuration for SAI1, UART5, and SPI3

2.12 CAN interface

The i.MX 91 processor supports a controller area network (CAN) module that is a communication controller

implementing the CAN protocol according to the CAN with flexible data rate (CAN FD) protocol and the CAN

2.0B protocol specification. The processor supports two CAN FD controllers.

On the FRDM-IMX91 board, one of the controllers is connected to the high-speed CAN transceiver

TJA1051T/3. The high-speed CAN transceiver drives CAN signals between the target processor and a 10-pin

2x5 2.54 mm header (P12) to its physical two-wire CAN bus.

The CAN_TXD and CAN_RXD signals are multiplexed on GPIO_IO25 and GPIO_IO27, respectively. On the

board, a 2-bit DIP switch (SW3) is used to control the CAN signals. For SW3 detail, see Section 1.7. The

CAN_STBY signal from the IO expander PCAL6524HEAZ (U725, P2_7, I2C address: 22) enables / disables

CAN standby mode.

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

21 / 34