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

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

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

Hope it can help you

BR

XiangJun Rong