• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 98 subscribers
  • Views 585 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

YAUQ (Yet another UART question) on AM335x EVM

Kurtis Unger
Prodigy 180 points

We would like to use the UARTs on the AM335x for our application.  For testing I would like to access one of the UARTs on the AM335x EVM.

From my understanding, after examinging am335x_gpevm_pinuse.xlsx, the CPLD code and the schematics, all the documentation indicates we should be able to access either:

- UART5 from the AM335x on UART2 (J12) of the daughterboard of the EVM with the EVM set to profile 6

OR

- UART2 from the AM335x on UART2 (J12) of the daughterboard of the EVM with the EVM set to profile 4

Unfortunately we cannot get any data out of J12 in either setting.  Any suggestions? 

Thanks in advance,

Kurtis

As further information:

- We do NOT need the LCD and it has been removed from our board.

- We have rebuilt the kernel with the FTDI drivers and we are able to communicate with ttyUSB0 over microcom

- I have read posts:

   http://e2e.ti.com/support/dsp/sitara_arm174_microprocessors/f/791/p/201131/719329.aspx#719329

   http://e2e.ti.com/support/dsp/sitara_arm174_microprocessors/f/791/t/194759.aspx

which seem very similar but I did not see a solution

  • 0
    Prodigy 180 points

    Just to answer my own question, this post was the most helpful...

    http://e2e.ti.com/support/arm/sitara_arm/f/791/t/178493.aspx

    which says the only profile that provides access to another UART (besides 0 and 1 for debug and bluetooth respectively) is profile 3 which brings out RX and TX of ttyO2 onto J12 of the daughterboard of the AM335x EVM.

    From reading

    http://processors.wiki.ti.com/index.php/AM335x-PSP_04.06.00.08_Release_Notes#What.27s_Supported

    for whatever reason the UARTs in profiles 4, 5, 6 are currently not supported.  Although we are running PSP_05_06.xxx at this point, I think this still applies.  Note that we did not need to apply any patch.

    So if you need a UART on the AM335x EVM, run in profile 3 on J12

    I would really like a full duplex UART (ie with CTS/RTS) so this is not an ideal solution but it's a step in the right direction.