CAN FILTERS

[puneethj]

Posted on November 11, 2015 at 17:50

Hi every one, especially Mr.Clive, today i have problem with CAN FILTERS i want to allow all IDS from 100 to 1FF in other words block all messages after 0x0200

here is my code, Please help me, Thanks in advance

void CAN_FilterConfiguration(void) {
CAN_FilterInitTypeDef CAN_FilterInitStructure;
/* CAN filter configuration */
// CAN_FilterInitStructure.CAN_FilterNumber = 0; // CAN 1
CAN_FilterInitStructure.CAN_FilterNumber = 14; // CAN 2
CAN_FilterInitStructure.CAN_FilterFIFOAssignment = CAN_FIFO0; // FIFO = 0
CAN_FilterInitStructure.CAN_FilterMode = CAN_FilterMode_IdMask; // Filter mode = identifier mask based filtering
CAN_FilterInitStructure.CAN_FilterScale = CAN_FilterScale_16bit;
CAN_FilterInitStructure.CAN_FilterIdHigh = 0x0100 << 5;
CAN_FilterInitStructure.CAN_FilterIdLow = 0;
CAN_FilterInitStructure.CAN_FilterMaskIdHigh = 0x01ff << 5;
CAN_FilterInitStructure.CAN_FilterMaskIdLow = 0;
CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;
//Interrrupts
CAN_ITConfig(CAN2,CAN_IT_FMP0,ENABLE);
CAN_FilterInit(&CAN_FilterInitStructure);
}

#!stm32f4-disco #can-filter

[Eugenia Suarez]

Posted on March 22, 2017 at 15:28

Lot of thanks, Clive!

[PRABU Appunu]

hi Clive

am working on STM32F417 with CAN extended ID .

i would like to reject the ID for example 0x0500xxxx.

I need to receive all messages which is > 0x0500xxxx.The only bit i need to check is 0x0500

I checked with ID masking mode , it was not possible to reject single ID .

I am not sure that ID list will serve this purpose .

How to reject signle ID using IDmasking or list mode ?

Appreciated to get some input

Thank YOU,

[Tesla DeLorean]

You filter the stuff you WANT to receive, it ignores the rest

[PRABU Appunu]

Clive,

i supposed to receive 50 CAN devices with specific ID's.

Instead of filtering those ID's , i would like to reject one single ID from that group and received rest of them without any issue.

I just want to filter CAN ID with 0x05000xxx...rest of ID's like 0x0501XXXX ,0x0502XXXX rest of all ID's i would like to receive.

i tried in ID MASK mode

filter _id 0x05001000

mask id 0x05FFF000

here i can only receive 0x05001XXX ID's which is logical.This is working fine.

But i want to reject only 0x05000xxx ID , which i coulnd't do it with masking .

Do you see any possibility here ?

Appreciated for the help

[PRABU Appunu]

Clive,

Did you see the any logic to reject the ID 0x0500xxx?

Thanks in advance for your help

[CJami]

Hi Clive,

i am facing a problem, i want to accept all messages to CAN except with the ID 0x17F00010 that uses a EXT ID. all my other messages are StdID. i am able to create filter that wastes the messages with IDs 0x10 but that also filters messages with ID like 0x710. need your help. Thanks in advance.

[Tesla DeLorean]

The filter only really allows for acceptance, you would need to have multiple filters to cherry pick things to reject by accepting everything around the specific thing you don't want. A narrow-band notch filter may be hard to achieve.

The mask should permit you to filter on STD/EXT ID. Bit 2 of the filter will be 1 for Extended Identifier Messages

What is the 29-bit ID you want to exclude? What other messages are you expecting? Create a list

[CJami]

i want to exclude the message with ExtId 0x17F00010 mean while i want to accept the messages with StidID 0x710.

[CJami]

if you can help me to make filter that passes the messages from 0x11 ...0x7FF, that will be great

[Uvess.1]

hi @Community member​ ,

I tried to understand with this examples but it's not obvious for me...

For exemple we want to accept address between 0x008 and 0x04F

So Filter_id_high = 0x008<<5

but i don't know how to calculate the mask....

EDIT1: so we've (MASK & ID) = 0x008

CAN_FilterInitTypeDef CAN_FilterInitStructure;
/* CAN filter configuration */
CAN_FilterInitStructure.CAN_FilterNumber = 14;
CAN_FilterInitStructure.CAN_FilterFIFOAssignment = CAN_FIFO0; 
CAN_FilterInitStructure.CAN_FilterMode = CAN_FilterMode_IdMask; 
CAN_FilterInitStructure.CAN_FilterScale = CAN_FilterScale_32bit;
CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;
CAN_FilterInitStructure.CAN_FilterIdHigh = 0x008 << 5; //11-bit ID in top bits
CAN_FilterInitStructure.CAN_FilterIdLow = 0;
CAN_FilterInitStructure.CAN_FilterMaskIdHigh = 0x??? << 5;
CAN_FilterInitStructure.CAN_FilterMaskIdLow = 0;

Thx in advance,

Uvess