topic Re: LPCExpresso 1549 UART in LPC Microcontrollers

LPCExpresso 1549 UART

adishpv — Thu, 06 May 2021 12:04:58 GMT

Hi,

I am using LPCExpresso 1549 evaluation board.

There are two micro USB ports in it namely target and link.

I connected the board to the PC using a link port. With LPCExpresso IDE I flashed an example code with UART prints. Now I could see the port detected in my PC as '/dev/ttyACM0'. The UART print worked fine.

Now I disconnected the board and connected again, but after the power cycle, the UART port is not enumerated in the PC.

Any suggestions will be really helpful.

Regards,

Adish

Re: LPCExpresso 1549 UART

diego_charles — Thu, 06 May 2021 19:58:22 GMT

Hi @adishpv

I hope you are doing well!

To narrow down this, from the MCU side:

Could you let me know which specific UART example are you running?
Check if the application firmware is running after the power cycle. For example, easy tests are verify if the MCU is not being held in reset state, or in Boot mode . By checking the state of RESET and ISP pins.

On the host side, you could check that there no problems with your Linux environment. testing with another OS like Windows 10 , if possible, could be an easy way.

Let me know your findings,

Diego.

Re: LPCExpresso 1549 UART

adishpv — Fri, 07 May 2021 04:46:09 GMT

Hi @diego_charles ,

Thanks for the reply.

To verify whether the firmware is running after reset I used the example "periph_blinky"

Once I flash the firmware image the LED starts blinking and this also enumerates a serial port "/dev/ttyACM0".

Now, when I power cycle the board, the LED blink works fine but the serial port is not enumerated.

So, my doubt is does UART over the link port in LPCExpresso 1549 board work only on debug mode?

Regards,

Adish

Re: LPCExpresso 1549 UART

frank_m — Fri, 07 May 2021 06:59:00 GMT

Do you speak about the LPCLink2 port, don't you ?

It seems you are working with Linux. Can you check if lsusb still lists the device after power-cycling the board ?

Perhaps your user just lacks the access rights to the USB device. How these are added depends on the actual distribution.

Re: LPCExpresso 1549 UART

adishpv — Fri, 07 May 2021 11:48:25 GMT

Hi @frank_m,

I am speaking about the LPCLink2 port.

Even after the power cycling on lsusb command, the device is still present.

The issue is after flashing the firmware with LPCExpresso IDE, there is a serial port enumerated.

But after the power cycle serial port is not enumerated.

Regards,

Adish

Re: LPCExpresso 1549 UART

diego_charles — Fri, 07 May 2021 16:06:07 GMT

Hi @adishpv

Thank you for your reply, In other words, the on board LPC link2 Debugger , after a Power cycle , can not be recognized as virtual com port, and It can only be recognized if you start a debug session, is correct?

Could you let us know more about your Linux Distribution? Which Distribution version is ,and if it is running under a virtual machine.

Re: LPCExpresso 1549 UART

adishpv — Fri, 07 May 2021 18:19:14 GMT

Hi @diego_charles,

What you said is right, I am not getting a com port after the power cycle.

I am using Ubuntu 18.04. I am not using a virtual machine.

Thanks and Regards,

Adish

Re: LPCExpresso 1549 UART

diego_charles — Fri, 07 May 2021 18:47:41 GMT

Hi @adishpv

To narrow this, could you try to update the on board debugger firmware? I do not know if you have the latest version.

All the best,

Diego

Re: LPCExpresso 1549 UART

adishpv — Fri, 07 May 2021 18:54:43 GMT

Hi @diego_charles,

Correct me If I am wrong, by saying debugger firmware you mean the firmware running on LPC4322 right?

Also, can you guide me with jumper options and steps to do the same?

Thanks,

Adish