Linux : Where is UART's

I'm interested in the UARTS myself.  I need RS232 support with CTS,RTS,DCD,and DTR.  Are these UARTS TTL or RS232 levels?  Is there support for the hardware control signals?

Thanks,

Chris

i don't found support with CTS,RTS,DCD,and DTR (maybe by GPIO)

however, I can confirm that the signal level is TTL for all UART

Hello,

Finaly I foud a solution to make UART 4&5 working.

I will try to write simple guide, how to achieve that.

Thanks to xizhou wang I was able to find the way how to do that.

1. In schematics http://www.element14.com/community/servlet/JiveServlet/previewBody/65504-102-1-287949/RIoTboard_Schematics.pdf on page 8 you can find how the UART 4&5 are pinned.  

So in file /linux-imx/arch/arm/mach-mx6/board-mx6dl_riot.h you have to add UART4&5

#if 0
        /* UART1 for debug */
        MX6DL_PAD_CSI0_DAT10__UART1_TXD,
        MX6DL_PAD_CSI0_DAT11__UART1_RXD,
#else
        /* UART2 for debug */
        MX6DL_PAD_EIM_D26__UART2_TXD,
        MX6DL_PAD_EIM_D27__UART2_RXD,
#endif
        /* UART3 */
        MX6DL_PAD_EIM_D24__UART3_TXD,
        MX6DL_PAD_EIM_D25__UART3_RXD,

        /********************** ADDED ***********************/
        /* UART4 */
        MX6DL_PAD_KEY_COL0__UART4_TXD,
        MX6DL_PAD_KEY_ROW0__UART4_RXD,

        /* UART5 */
        MX6DL_PAD_KEY_COL1__UART5_TXD,
        MX6DL_PAD_KEY_ROW1__UART5_RXD,
        /***************************************************/

2. Then in /linux-imx/arch/arm/mach-mx6/board-mx6q_riot.c you have to initialize UART 4&5

static inline void mx6q_riot_init_uart(void)
{
        imx6q_add_imx_uart(0, NULL);
        imx6q_add_imx_uart(1, NULL);
        imx6q_add_imx_uart(2, NULL);
         
/********************** ADDED ***********************/
        imx6q_add_imx_uart(3, NULL);
        imx6q_add_imx_uart(4, NULL);
/***************************************************/
}

And now you have to recompile the kernel and flash it to your RiotBoard.

After that you will have:

/dev/ttymxc0 - still don't know what is for

/dev/ttymxc1 - debug serial port

/dev/ttymxc2 - UART3

/dev/ttymxc3 - UART4

/dev/ttymxc4 - UART5

Hope it will help

Marek Czudek wrote:

 

/dev/ttymxc0 - still don't know what is for

it's hooked up to the OpenSDA debugger via U26 on p20 of the schematics.  Some info on OpenSDA is available here https://www.pemicro.com/opensda/ and the user guide http://cache.freescale.com/files/32bit/doc/user_guide/OPENSDAUG.pdf

It's briefly mentioned on p33 of the user manual with the note at the bottom of the page that says

The RIoTboard has hardware to support Freescale’s OpenSDA interface. Currently this

interface has not been enabled in software

so apparently ttymxc0 is unusable as the OpenSDA hardware appears to be the only way to get to it and for some unknown reason it has no software support.

Indeed, following the instructions from the OpenSDA user manual gets no response. No usb storage device appears. You'd have to assume therefore that whatever firmware is supposed to be loaded onto the Kinetis K20 is missing.  Only a guess, but loading it may take jtag onto the un-populated J17.

Marek Czudek wrote:

 

/dev/ttymxc0 - still don't know what is for

it's hooked up to the OpenSDA debugger via U26 on p20 of the schematics.  Some info on OpenSDA is available here https://www.pemicro.com/opensda/ and the user guide http://cache.freescale.com/files/32bit/doc/user_guide/OPENSDAUG.pdf

It's briefly mentioned on p33 of the user manual with the note at the bottom of the page that says

The RIoTboard has hardware to support Freescale’s OpenSDA interface. Currently this

interface has not been enabled in software

so apparently ttymxc0 is unusable as the OpenSDA hardware appears to be the only way to get to it and for some unknown reason it has no software support.

Indeed, following the instructions from the OpenSDA user manual gets no response. No usb storage device appears. You'd have to assume therefore that whatever firmware is supposed to be loaded onto the Kinetis K20 is missing.  Only a guess, but loading it may take jtag onto the un-populated J17.