COM UART debug on OM13285 board

[sohanw]

Hello,

I am trying to get the debug output working for OM13285 (https://www.nxp.com/docs/en/user-guide/UM10798.pdf) over the serial UART, with COM port connector on board.

Can anyone point me to an example which I can use to get this up and running? This is only for demonstration and test purposes so a quick way over the best way is preferred!

Thanks in advance!

Regards

[jeremyzhou]

Hi  Sohan Walimbe,

Thank you for your interest in NXP Semiconductor products and 

the opportunity to serve you.

To provide the fastest possible support, I'd recommend you to refer to the rb_uart demo in the LPCXpreso LPC1343 board LPCOpen library: LPCOpen Software for LPC13XX|NXP 

Have a great day,
TIC

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[sohanw]

Hi jeremyzhou‌,

I tried the periph_uart_rb example but there is no output on COM port if I build it as it is. I don't have a debugger so I tried to toggle the on-board LED in  the Systick_Handler, but that didn't work either.

Another example periph_i2c does toggle the LED in Systick_Handler, but still does not show any output on COM port. In fact the TXD line (PIO 0_7 on the board or pin 2 on the connector) seems to (coincidentally?) toggle at the same rate as the LED.

Note that I have enabled DEBUG_ENABLE and tried with or without NO_BOARD_LIB as well. Do I need to do any different clock and/or port mapping configurations for this specific board? I could not figure out anything different from the manual (https://www.nxp.com/docs/en/user-guide/UM10798.pdf).

Regards

[jeremyzhou]

Hi Sohan Walimbe,

Thanks for your reply.

I'd highly recommend you to confirm whether the hardware configuration is correct or not, it's crucial.

Have a great day,
TIC

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[sohanw]

Hi jeremyzhou‌,

Nothing has been modified on the original OM13285 board. The schematic in the manual (https://www.nxp.com/docs/en/user-guide/UM10798.pdf ) is unchanged.

Regards

[jeremyzhou]

Hi Sohan Walimbe,

Thanks for your reply.

After setting the DEBUG_ENABLE, the UART pins will be mapped via following codes.

And I think you need a debugger, and it would be better when having oscilloscope too.

   {(uint32_t)IOCON_PIO1_6,  (IOCON_FUNC1 | IOCON_RESERVED_BIT_6 | IOCON_RESERVED_BIT_7 | IOCON_MODE_INACT)}, /* PIO1_6 used for RXD */
    {(uint32_t)IOCON_PIO1_7,  (IOCON_FUNC1 | IOCON_RESERVED_BIT_6 | IOCON_RESERVED_BIT_7 | IOCON_MODE_INACT)}, /* PIO1_7 used for TXD */‍‍

Have a great day,
TIC

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[sohanw · Accepted solution]

Hi jeremyzhou‌,

Thanks for your reply. After digging into it, I have found that the schematic of OM13285 has incorrect connection for UART TXD pin. So I removed the pin P0.7 on LPCXpresso LPC1343 board completely by desoldering. And connected the TXD pin to P0.7 from the bottom side of OM13285 PCB. This seems to work!

For future reference: The board OM13285 Rev 2.2 has this issue. NXP will possibly fix this in the future revisions.

Regards

[jeremyzhou]

Hi Sohan Walimbe,

Thanks for your information, and I'll report this issue for the Document team for further checking.

Have a great day,
TIC

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[sohanw]

Hi jeremyzhou‌,

The documentation itself is correct, the schematic has incorrect connection of TXD pin. Perhaps you should report this to the circuit/PCB design team.

Regards

[jeremyzhou]

Hi Sohan Walimbe,

Okay, I get it.
Have a great day,
TIC

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------