FRDM-KEAZ128 debug mode

[283230333]

I have a FRDM-KEAZ128 development board （part number FRDM-KEAZ128Q80）. There is a MC33903 SBC chip on the development board. I want to develop CAN now, but I don't want to configure the MC33903. I noticed that the MC33903 has a debug mode and can use the CAN transceiver without configuring the MC33903 via SPI. How to configure the circuit in the picture?

[kerryzhou]

Hi Logan,

    If you want to configure the MC33903 in debug mode, you need to follow that chip's datasheet:

I suggest you control the SPI interface to enable the CAN module.

Actually, in the community, there has a sample code for your reference, you can refer to it:

FRDM-KEAZ128Q80 MSCAN Communication 

MSCAN_Driver+FRDM_KEA128 Example_TransmitPerSecond.zip

It is S32DS on FRDM-KEAZ128 board.

You can try this code:

Have a great day,
Kerry

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[283230333]

Does it need to connect 12V power at J16?  I don't have 12v power supply ， I only have the USB interface . Is this okay？

[kerryzhou]

Hi Logan,

  Yes, you are right, this board need to connect 12V power at J16, J107 need to connect pin1,2.

  The bit rate is 500Kpbs, this is my test result:

Actually, 12V power is very easy to find.

If you don't want to use 12V, you also can use our TRK-KEA128 board, that board CAN transiver don't need the external 12V, just USB cable is OK.

Wish it helps you!

Have a great day,
Kerry

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[283230333]

没有12V真的可以吗？我现在仅仅用USB来供电，但是你发的例程，CAN信号就是出不来。我看了一下开发板的原理图。J107这个地方，如果接通23那么就是USB给单片机供电。如果接通12，那么就是SBC给单片机供电。也就是如果没有12V，那么SBC是没有电的，那么CAN收发器也就用不了。我是这样理解的。你可以去掉12V，仅仅用USB供电，然后试一下。如果能用的话，你拍个照片，我看看你开发板是怎么设置的。

[kerryzhou]

在FRDM-KEA128板子上，没有12V真的不可以！

我已经试过了，你看我上面的结果呢，USB不行的。

所以我建议你，如果想只用USB，你用TRK-KEA128，那个板子的外部CAN收发器控制很简单，只控制CAN数据收发就行了。

Have a great day,
Kerry

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