Can transmit but cannot receive at CAN-FD 5Mbps

[araki]

Hi all,

I’m evaluating FRDM-MCXN947 with CAN-FD but I’m currently facing trouble to use it. Can you tell me any ideas? I’m re-using the SDK example project of flexcan_interrupt_transfer.

• CAN system clock: 100MHz from PLL1CLK0 without division
• CAN arbitration bit rate: 500kbps
• CAN-FD data rate: 5Mbps
• CAN clock prescaler: /2
• PROPSEG of CAN: 56tq
• PSEG1 of CAN: 18tq
• PSEG2 of CAN: 18tq
• JSW of CAN: 18tq
• PROPSEG + PSEG1 of CAN-FD: 10tq
• PSEG2 of CAN-FD: 7tq
• JSW of CAN-FD: 7tq

I’m not sure why the total number of time quantum isn’t 96 but 92. However, when I set the PROPSEG to 60tq from 56tq for example, the device neither sends nor receives. I tried to utilize the function of FLEXCAN_FDCalculateImprovedTimingValues() but the values set by the function don’t work at even 2Mbps CAN-FD.

[xiangjun_rong]

Hi,

I have checked the SDK example flexcan_interrupt_transfer

xiangjun_rong_0-1716187157502.png

The CTRL2[BTE] bit is set, which means that EPRS, ENCBT and EDCBT registers determines the nominal and data bit rate.

xiangjun_rong_1-1716187550083.png

You can calculate the CAN bit rate based on the red circle register setting.

Hope it can help you

BR

XiangJun Rong