Nucleo-144 CAN bus example code?

[Dick Lin]

Posted on May 30, 2018 at 21:08

Hi,

I am using STM32L496 with Nucleo-144/STM32CubeMX.

Is there any CAN BUS example with HAL Drivers? I can't even find how to setup the baudrate.

Thanks,

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[Tesla DeLorean]

Posted on May 30, 2018 at 22:19

Try looking at this (L4x6 family RM0351)

STM32Cube_FW_L4_V1.11.0\Projects\STM32L476G-EVAL\Examples\CAN\CAN_Networking

Baud is derived from APB clock divided by Prescaler, and subdivided by sum of SJW+BS1+BS2 quanta

[Dick Lin]

Posted on May 30, 2018 at 22:39

Got it. Thx

How to setup the baudrate? Probably in this MX_CAN1_Init(). I just haven't figured which code is doing the baudrate.

/* CAN1 init function */

void MX_CAN1_Init(void)

{

hcan1.Instance = CAN1;

hcan1.Init.Prescaler = 16;

hcan1.Init.Mode = CAN_MODE_NORMAL;

hcan1.Init.SyncJumpWidth = CAN_SJW_1TQ;

hcan1.Init.TimeSeg1 = CAN_BS1_1TQ;

hcan1.Init.TimeSeg2 = CAN_BS2_1TQ;

hcan1.Init.TimeTriggeredMode = DISABLE;

hcan1.Init.AutoBusOff = DISABLE;

hcan1.Init.AutoWakeUp = DISABLE;

hcan1.Init.AutoRetransmission = DISABLE;

hcan1.Init.ReceiveFifoLocked = DISABLE;

hcan1.Init.TransmitFifoPriority = DISABLE;

if (HAL_CAN_Init(&hcan1) != HAL_OK)

{

_Error_Handler(__FILE__, __LINE__);

}

}

[Tesla DeLorean]

Posted on May 31, 2018 at 14:21

These lines impact the wire speed

hcan1.Init.Prescaler = 16;

hcan1.Init.SyncJumpWidth = CAN_SJW_1TQ;

hcan1.Init.TimeSeg1 = CAN_BS1_1TQ;

hcan1.Init.TimeSeg2 = CAN_BS2_1TQ;

APBClock / (16 * 3)

APBClock /48

The specific bit rate on the CAN bus will depend on how fast you're clocking your process/buses, which you don't specify