TWR K70F120M and FlexCAN example

[raulmoneo]

Please need some help with FlexCAN example in TWR K70F120M.

This example requires two Towers, At the beginning I only had one so I've set FlexCAN in LOOPBACK mode and It seems to work well, I saw the interrupt each second.

Now I have a CAN emulator and I've set it to listen without any filter and I've set back FlexCAN example to NORMAL mode but I don't see any traffic in the bus.

I've checked the CAN emulator listen ok at the same baude rate with other CAN device.

TWR-SER J5 settings:

1-2   close

3-4   open

5-6   close

7-8   close

9-10 close

J4 open

Someone have run FlexCAN example in TWR K70F120M? any advice?

Thanks in advance

Raúl

[santiago_gonzal]

Hello Raul,

I have tested the MQX example project of FlexCAN in the past, and it worked between two TWR boards without any problem.

Could you check with a Scope if the output pins of the MCU (CanRX and CanTX) are showing activity?

Do you know if you CAN listener adds a end of line resistance?

Regards,

Santiago

[raulmoneo]

Hi Santiago,

Thanks for your reply.

There is no any activity in the bus. CAN_H and CAN_L both stay in high level.

I've connected emulator to other CAN devices and it works I guest it has end of line resistance but not sure.
I've run the example connecting the tower to this circuit I found in the forum but I don't see activity in the scope.

CAN_H ________________

               |                       |

               |                     _|_

             -----  47nF         |__|  56Ohm

             -----                     |

               |___ | |________|

               |      | |  0.1uF    |

               |                       |

               |                     _|_

             -----  47nF         |__|  56Ohm

             -----                     |

CAN_L __|_____________|

Any suggestion?

Thanks in advance.

Raul

[santiago_gonzal]

Hi Raul,

Please, check the CAN RX and CAN TX signals from the MCU. You can have access to them using the through hole connectors in the outside part of the TWR-Elevators. The CAN RX and TX are the B41 and B42 pins.

If you don't see activity on the pins I will try with my own board. Can you tell me/share what project are you exactly using?

Regards,

Santiago

[raulmoneo]

Hi,

Yes, I did it.

When I generate traffic with the emulator I see traffic in B41 but interrupt don't happen.

The can example (TX task) sends a frame each second but nothing appears in B42.

I attach here the project. I created a project based on the example of Flexcan. The source code is taken from "MQX_DIR\mqx\examples\can\flexcan\"

Thanks for your help.

Raúl

[raulmoneo]

Hi,

I got a second tower K70F120M.

I created, built and downloaded FlexCAN example with NODE 1 and NODE 2. I've connected Pin CAN_H with CAN_H and CAN_L with CAN_L.

I don't see any bus activity.

I've debugged driver, checking CAN registers and It seems to follow the configuration steps that "FlexCAN_training_material.pdf" says.

Any advice?

Thanks.

[raulmoneo · Accepted solution]

The answer here

https://community.freescale.com/thread/317691