Freemodbus issue with MCUXpresso / LPCXpresso

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Freemodbus issue with MCUXpresso / LPCXpresso

Contributor I

Hi everyone!

I have always used the FreeModbus library with the LPCXpresso IDE (an old version), and I have never had problems. However, when I installed MCUXpresso and opened the same proyect that I used to open with LPCXpresso, I sarted to have parity problems, that is, when I set the modbus configuration in "no parity" I don't have any problem, but when I set it in EVEN or ODD, the message that I receive is not correct, like a parity error(I'm using Modbus RTU slave).

It seems very strange to me, due to I don't have problems with the modbus with LPCXpresso.

Did anyone have a simmilar issue before?


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4 Replies

NXP Employee
NXP Employee

Hello ,

Hope you are doing well.

Could you please provide the microcontroller that you are using as well as the MCUXpresso IDE version and SDK version.

Best Regards,



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Contributor I

Hello Sabina, 

The microcontroller is the LPC1769. I've tried with 2 or 3 versions of MCUXpresso and LPCXpresso. My last test was with MCUXpresso V11.1.1 and LPCXpresso 6.1.2.

I don't have SDKs installed.

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NXP Employee
NXP Employee

Hope you are well. In the case of the lpc17xx, it does not have an SDK so the examples must be imported from the LPCOpen folder. The path in your computer will be the following:



You may import the available examples by clicking "Import project from file system" in the quick start menu. Select the zip folder option and browse to the above path.

Here you will find the different packages for several microcontrollers.


Select your microcontroller and you may use the examples as reference with the latest version available. Could you please try these examples and see if they work for you. If so, then I'd recommend to port your example using these drivers to see if anything was updated as well. It is strange that a difference in the IDE would be causing a behavior such as not working. 

You may also try a simple blink example to make sure that the MCUXpresso IDE is setup correctly. 


Please let me know your results.

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Contributor I

Thank you, I'll test it soon and let you know the results.


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