Can transmit but cannot receive at CAN-FD 5Mbps

araki — Mon, 20 May 2024 01:50:56 GMT

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.

Re: Can transmit but cannot receive at CAN-FD 5Mbps

xiangjun_rong — Mon, 20 May 2024 06:47:17 GMT

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

XiangJun Rong

topic Re: Can transmit but cannot receive at CAN-FD 5Mbps in MCX Microcontrollers

Can transmit but cannot receive at CAN-FD 5Mbps

Re: Can transmit but cannot receive at CAN-FD 5Mbps