AURIX tc387 -CAN Frame limitted number

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yangliu
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We are going to use Tc387 as the gateway and use 12 can nodes to recieve and transmitte the CAN messgage.
And now I wonder the single CAN node limitation to recieve and transmitte the frames.
How many frames is the Limitation of one single CAN node?I couldn`t find any thing in the manual.
Now the chassis CAN frame is 7000 per second.
Can tc387  satisfy  the 12xCAN(25000 frame per second in total)?
Thank you !
 
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Di_W
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TC3XX series MCMCAN module supports classic CAN and CAN FD, besides frame per second, you should also consider Total Frame Length and Bandwidth Usage. i.e. 8 data bytes (64bits) may need ~135bits total length for 1 frame.
Otherwise, you should give more redundant bandwidth for fault tolerance. For 1Mbps/500bps/250bps classical CAN baud rate, if that not fulfill your demand, maybe CAN FD is another choice. However you should consider if all your nodes are CAN FD compatible?

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yangliu
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Thank you for the reply.

We`re using the standard CAN and it`s 500bps.

But the Chassis CAN you know should be busy. We detect that the CAN frame number is about 7000.

Now the Tc387 dealing with 7000 frames is ok,but we need other CAN domain in the CAR and tc387 have 12 CAN nodes.So I wonder the 387`ablity to unpack and pack the CAN frames.

Do you know something about this ?

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Di_W
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Hi yangliu

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Di_W
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Hi yangliu,
What you should consider is the frame rate of each CAN node, in general, 500kbps, 64bit/frame, the full payload is 7,812frame/s,
1. But full payload is ideal, not in practice
2. That's just one Node case
3. From MCU, assuming that 12 channels of CAN are used at the same time, at 500kbps, the limit load is 7,812 * 12 frames per second, in fact, it is unlikely that 12 channels are full payload, and different node has different bandwidth payload
4. To consider the time of MCU processing, suppose a certain CAN node is about 1000frame/s, then 1ms trigger an interrupt, the processing should be completed in time in the interrupt routine, the specific processing time should be determined according to your application, i.e. a  8 bytes package unpacking, packet processing, then you could estimate the specific processor time according to instruction circle number , our processor can run 160MHz to 300MHz according to different series, and the specific instruction cycle after C compilation determines the specific processing time. It also needs a systematic analysis.

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yangliu
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Thank you for the reply.

I`m going to test the process time and load to evaluate the project.Then analysis the data.

😆

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