BeagleBone Black enabling UART ports

Do I understand it correctly?

uart1: serial@48022000 {
pinctrl-names = "default";
pinctrl-0 = <&uart1_pins>;

status = "okay";
};

and

uart1_pins: pinmux_uart1_pins {
pinctrl-single,pins = <
0x180 (PIN_INPUT_PULLUP | MUX_MODE0) /* uart1_rxd.uart1_rxd */
0x184 (PIN_OUTPUT_PULLDOWN | MUX_MODE0) /* uart1_txd.uart1_txd */
>;
};

So i did it and compiled dtb file according to guide from this page: http://processors.wiki.ti.com/index.php/Linux_Kernel_Users_Guide

I replaced old am335x-boneblack.dtb with new one and launched the device. There is still no /dev/ttyO1 in system. What i did wrong?

Here are another detailed instructions to enable UART2 on BB:

blog.pignology.net/.../getting-uart2-devttyo1-working-on.html

http://hipstercircuits.com/enable-serialuarttty-on-beaglebone-black/

I modified am335x-bone-common.dtsi file and compiled am335x-boneblack.dtb again and now i can see /dev/ttyO1. Now I'm trying to work with it, to establish connection with another device.

I've seen those guides you wrote in previous message, but they didn't help.

As it can be verified in BBB Documentation, only UART2, 4 and 5 are using same pins with Ethernet.
Look into 6.8.1 Ethernet Processor Interface here:
github.com/.../BBB_SRM.pdf

BR,
Georgi

UART1 works fine now. Also i need 2 more ports, so I tried to activate UART2. I did next steps:

1) Added this:

uart2_pins: pinmux_uart2_pins {
			pinctrl-single,pins = <
				0x12c (PIN_INPUT_PULLUP | MUX_MODE1)	/* uart2_rxd.uart2_rxd */
				0x130 (PIN_OUTPUT_PULLDOWN | MUX_MODE1)	/* uart2_txd.uart2_txd */
			>;
		};

and this:

uart2: serial@48024000 {
			pinctrl-names = "default";
			pinctrl-0 = <&uart2_pins>;

			status = "okay";
		};

Mux mode changed to "1", according to reference manual  7.1.2 Connector P9, Table 13.

2) Commented lines with the same pins (0x12c, and 0x130):

Here:

cpsw_default: cpsw_default {
			pinctrl-single,pins = <
				/* Slave 1 */
				0x110 (PIN_INPUT_PULLUP | MUX_MODE0)	/* mii1_rxerr.mii1_rxerr */
				0x114 (PIN_OUTPUT_PULLDOWN | MUX_MODE0)	/* mii1_txen.mii1_txen */
				0x118 (PIN_INPUT_PULLUP | MUX_MODE0)	/* mii1_rxdv.mii1_rxdv */
				/*0x11c (PIN_OUTPUT_PULLDOWN | MUX_MODE0)*/	/* mii1_txd3.mii1_txd3 */
				/*0x120 (PIN_OUTPUT_PULLDOWN | MUX_MODE0)*/	/* mii1_txd2.mii1_txd2 */
				0x124 (PIN_OUTPUT_PULLDOWN | MUX_MODE0)	/* mii1_txd1.mii1_txd1 */
				0x128 (PIN_OUTPUT_PULLDOWN | MUX_MODE0)	/* mii1_txd0.mii1_txd0 */
				/*0x12c (PIN_INPUT_PULLUP | MUX_MODE0)*/	/* mii1_txclk.mii1_txclk */
				/*0x130 (PIN_INPUT_PULLUP | MUX_MODE0)*/	/* mii1_rxclk.mii1_rxclk */
				0x134 (PIN_INPUT_PULLUP | MUX_MODE0)	/* mii1_rxd3.mii1_rxd3 */
				0x138 (PIN_INPUT_PULLUP | MUX_MODE0)	/* mii1_rxd2.mii1_rxd2 */
				0x13c (PIN_INPUT_PULLUP | MUX_MODE0)	/* mii1_rxd1.mii1_rxd1 */
				0x140 (PIN_INPUT_PULLUP | MUX_MODE0)	/* mii1_rxd0.mii1_rxd0 */
			>;
		};

And here:

		cpsw_sleep: cpsw_sleep {
			pinctrl-single,pins = <
				/* Slave 1 reset value */
				0x110 (PIN_INPUT_PULLDOWN | MUX_MODE7)
				0x114 (PIN_INPUT_PULLDOWN | MUX_MODE7)
				0x118 (PIN_INPUT_PULLDOWN | MUX_MODE7)
				/*0x11c (PIN_INPUT_PULLDOWN | MUX_MODE7)*/
				/*0x120 (PIN_INPUT_PULLDOWN | MUX_MODE7)*/
				0x124 (PIN_INPUT_PULLDOWN | MUX_MODE7)
				0x128 (PIN_INPUT_PULLDOWN | MUX_MODE7)
				/*0x12c (PIN_INPUT_PULLDOWN | MUX_MODE7)*/
				/*0x130 (PIN_INPUT_PULLDOWN | MUX_MODE7)*/
				0x134 (PIN_INPUT_PULLDOWN | MUX_MODE7)
				0x138 (PIN_INPUT_PULLDOWN | MUX_MODE7)
				0x13c (PIN_INPUT_PULLDOWN | MUX_MODE7)
				0x140 (PIN_INPUT_PULLDOWN | MUX_MODE7)
			>;
		};

After that I recompiled dtb file and changed one on the board. Now i see /dev/ttyO2. But i can't see any data on the port when i'm trying to write to it. I'm checking it using oscilloscope and there is nothing on the both lines. But at the same time /dev/ttyO1 is works fine and I can use it for data exchange with another devices. Please tell me where i did mistake.