Mity CPU Platforms » MityDSP-L138 (ARM9 Based Platforms)

Aviv Prital wrote:

Hi,

I'd like to use MitydspL138F Expansion port to get another serial connection to be used by Linux application.
What should be done for this (at U-boot, kernel, etc)?
I found some 6 years old related thread which was not completed:
https://support.criticallink.com/redmine/boards/10/topics/3548

To use a peripheral on the L138 you need to ensure the pinmux is set correctly and the appropriate driver is enabled.

UART2 is already setup in the kernel for use as an RS-485 port (though without the RS485 adapter its the same as a UART). These pins go to the J504 connector on the industrial io devkit. You can find the devkit schematics here: https://support.criticallink.com/redmine/projects/indio/wiki/Industrial_IO_Revision_Information

• The pinmux in the kernel is setup for UART2, so you should be able to use it by accessing /dev/ttyS2
  baseboard-industrialio.c
  

    /**
     * UART2 Pins for expansion port (RS-485 port).
     */
    static short baseboard_uart2_pins[] __initdata = {
    >---DA850_UART2_RXD,
    >---DA850_UART2_TXD,
    >----1,
    };
  

I'm also curious about enabling UART2 from bare-metal dsp code.

As long as the pins are pinmuxed, either in u-boot, linux, or your dsp code. Then you shouldn't have a problem using UART2. http://www.ti.com/lit/ug/sprufm6c/sprufm6c.pdf