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How to use ttyS0?

PaulLee
Intellectual 480 points
Other Parts Discussed in Thread: AM1808, DA8XX

Hi, everyone.

I have a board using AM1808 made by some company which is not available now.

I am porting linux 2.6.3 kernel.

I have a circuit diagram of the board.

In the board, UART1/2 are used for debug and RS-485.

But UART0 is assigned to WiFi daughter board connector.

I think UART0 pin may be assigned for WiFi connection.

I checked by inputing "echo asdjfkdsf > /dev/ttyS0" by console, no signal on UART0 pin.

How can I check this UART0 RX/TX pins are assigned to which function?

How can I assigned UART0 RX/TX pins for UART0?

I don't have a plan to use WiFi function.

Kernel? or u-boot?

BR

Paul 

  • 0
    TI__Guru** 116100 points
    Dear Paul,
    You have to check the board file in linux source code.
    linux-source/arch/arm/mach-davinci/

    Also you have to check AM1808 TRM guide (technical reference manual) to know the shared peripherals with UART.

    I hope, all OMAPL13x/AM18x EVM board has console port using UART2 only.

    I'm sure that UART0 is not used for WiFi since UART0 pins are muxed with EMAC (MII pins), GPIO, and SPI CS pins (CS4 and CS5),
    Please check the board file as I said, I hope UART0/CS/MII/GPIO pins used/selected for Ethernet.

    What you are trying to do ?
    Need to access UART0 ?
  • 0
    Intellectual 480 points
    Dear, Titusrathinaraj,

    Yes, I need to access UART0.
    I will check some board file in mach-davichi/*
    I want to know is where and which file enable UART1.
    UART1 is enabled by my Kernel already.
    Searching the part of enabling UART1, then do same manner for enabling UART0.
    How is My idea?

    Thanks
    Paul
  • 0 in reply to PaulLee
    TI__Guru** 116100 points
    Dear Paul,
    You have to enable the UART0 in u-boot and comment the following line in board file.

    __raw_writel(0, IO_ADDRESS(DA8XX_UART0_BASE) + 0x30);


    You have to do PINMUX for UART0 in u-boot.
    PS: You can't use ethernet since its pinmuxed with MII interface.

    Please share the schematic of that board, will check and let you know.