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Configure CAN filter to accept all messages

S G
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Hi All,

Really need help on this one, any suggestions welcome!....

I'm using the CAN bus example program for MCBSTM32C eval board. It has an STM32F107 chip and I am have issues with the CAN Filter....

Does anyone know how to configure the CAN Filter to accept ALL incoming messages?

Thanks

Shane

Parents
  • 0 Offline in reply to S G

    There supposed to be some functions in ST's OOXX_StdPeriph_Driver Library like:

    void CAN_FilterInit(CAN_FilterInitTypeDef* CAN_FilterInitStruct);

    Maybe see this:

    my.st.com/.../Flat.aspx

    Agree, the documentation is a little confusing. The short answer is that the FilterIDLow
and FilterIDHigh as well as MaskIDLow and MaskIDHigh don't correspond exactly to the SID/EID.
The bits need to be shifted depending on the type of ID you are trying to filter. It took me
several weeks to find the answer on a German website that I used google to translate. Please
look at my example code below, hopefully it will be clear then.

In this example four filters are created to receive only SID 123, 124, 125 and 126. They
don't have to be in order, just happened to be the numbers I picked. For a SID the numbers
for the Filter/Mask IDs need to be shifted to the left by 5 bits.

CAN_FilterInitStructure.CAN_FilterNumber = 1;
CAN_FilterInitStructure.CAN_FilterMode = CAN_FilterMode_IdList;
CAN_FilterInitStructure.CAN_FilterScale = CAN_FilterScale_16bit;
// All filters are shifted left 5 bits
CAN_FilterInitStructure.CAN_FilterIdHigh = 0x2460;          // 0x123
CAN_FilterInitStructure.CAN_FilterIdLow = 0x2480;           // 0x124
CAN_FilterInitStructure.CAN_FilterMaskIdHigh = 0x24A0;      // 0x125
CAN_FilterInitStructure.CAN_FilterMaskIdLow = 0x24C0;       // 0x126
CAN_FilterInitStructure.CAN_FilterFIFOAssignment = 0;
CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;
CAN_FilterInit(&CAN_FilterInitStructure);

Reply
  • 0 Offline in reply to S G

    There supposed to be some functions in ST's OOXX_StdPeriph_Driver Library like:

    void CAN_FilterInit(CAN_FilterInitTypeDef* CAN_FilterInitStruct);

    Maybe see this:

    my.st.com/.../Flat.aspx

    Agree, the documentation is a little confusing. The short answer is that the FilterIDLow
and FilterIDHigh as well as MaskIDLow and MaskIDHigh don't correspond exactly to the SID/EID.
The bits need to be shifted depending on the type of ID you are trying to filter. It took me
several weeks to find the answer on a German website that I used google to translate. Please
look at my example code below, hopefully it will be clear then.

In this example four filters are created to receive only SID 123, 124, 125 and 126. They
don't have to be in order, just happened to be the numbers I picked. For a SID the numbers
for the Filter/Mask IDs need to be shifted to the left by 5 bits.

CAN_FilterInitStructure.CAN_FilterNumber = 1;
CAN_FilterInitStructure.CAN_FilterMode = CAN_FilterMode_IdList;
CAN_FilterInitStructure.CAN_FilterScale = CAN_FilterScale_16bit;
// All filters are shifted left 5 bits
CAN_FilterInitStructure.CAN_FilterIdHigh = 0x2460;          // 0x123
CAN_FilterInitStructure.CAN_FilterIdLow = 0x2480;           // 0x124
CAN_FilterInitStructure.CAN_FilterMaskIdHigh = 0x24A0;      // 0x125
CAN_FilterInitStructure.CAN_FilterMaskIdLow = 0x24C0;       // 0x126
CAN_FilterInitStructure.CAN_FilterFIFOAssignment = 0;
CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;
CAN_FilterInit(&CAN_FilterInitStructure);

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