S32KのトピックRe: How to set CAN0 RX to be High Impedance

How to set CAN0 RX to be High Impedance

whale — Wed, 08 Jan 2025 01:06:11 GMT

MCU：S32K144
SDK：Without SDK

操作：通过配置CAN0（PTB0，PTB1）实现CAN通信。
现象：CAN通信正常，但是在CAN RX(PTB0)也检测到了输出信号，因此现在想将PTB0设置为High Impedance，确保在进行CAN通信时，PTB0不输出信号，该如何操作？下列这个操作是对的吗？

// CAN0

CAN0_PORT->PCR[CAN0_RX_PIN] |= PORT_PCR_MUX(5); /* Port B0: MUX = ALT5, CAN0_RX */

CAN0_PORT->PCR[CAN0_TX_PIN] |= PORT_PCR_MUX(5); /* Port B1: MUX = ALT5, CAN0_TX */

// Set CAN0 RX High Impedance

PTB->PDDR &= ~0x01;

Re: How to set CAN0 RX to be High Impedance

whale — Wed, 08 Jan 2025 03:21:48 GMT

CAN transceiver：TCAN1162

Re: How to set CAN0 RX to be High Impedance

PetrS — Wed, 08 Jan 2025 09:26:34 GMT

Hi,

selecting CAN RX function in PCR register a PTB0 pin operate as input. You do not need to set direction.
Signal comes from CAN transceiver, in normal mode its RXD pin follows bus signal.
When FlexCAN is sending frame, it must see the same on its RXD line to be able to detect possible errors.

BR, Petr