PSoC5 CAN: How to achieve 250kbps CAN speed w/o external clock source

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Anonymous
Not applicable

Hello Team,

          We are using Cy8ckit-001 EVK Board and CY8C5868-LP035 module. We are trying to implement CAN module which receive and transmit data from another board. We want to achieve CAN baud rate of 250kbps. But CAN_v_3.0 datasheet says

          In order for CAN component to operate properly. The accuracy of clock used (BUS_CLK for PSoC 3/PSoC 5LP) must match the CAN clock tolerance requirement which is 0.5% or better for bit-rates faster than 125kbps. But with the help of internal clock we are not able to achieve 0.5% tolerance. PSoC Creator is giving following warning.

pastedImage_8.png

Following is my jpeg of clock tree.

pastedImage_10.png

               Please guide me how to configure clock tree and can module to achieve 250kbps can speed without external crystal.

Thanks and Regards,

Abhishek.

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1 Solution
harshadap_76
Employee
Employee
First like received

Hi Abhishek,

In order to use more acurate clock you need to use external crystal on your board and you have to select XTAL in the clock tree. Kindly have a look at the following figure:

pastedImage_0.png

Also for more information please refer AN52701 - PSoC® 3 and PSoC 5LP - Getting Started with Controller Area Network (CAN) | Cypress Semico... .

As PSoC 5LP module already has a crystal on it, you need to just select XTAL as above and proceed.

Regards

Harshada

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1 Reply
harshadap_76
Employee
Employee
First like received

Hi Abhishek,

In order to use more acurate clock you need to use external crystal on your board and you have to select XTAL in the clock tree. Kindly have a look at the following figure:

pastedImage_0.png

Also for more information please refer AN52701 - PSoC® 3 and PSoC 5LP - Getting Started with Controller Area Network (CAN) | Cypress Semico... .

As PSoC 5LP module already has a crystal on it, you need to just select XTAL as above and proceed.

Regards

Harshada

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