DESK-MX6UL-L/Peripherals/UART
< DESK-MX6UL-L
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Contents
Peripheral UART[edit | edit source]
Device tree configuration[edit | edit source]
Here below an example of device tree configuration used on standard DAVE's kit for the AXEL ULite SOM:
From the Carrier imx6ul-lynx-som0013-cb002f.dts device tree:
&uart2 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart2_flow>;
fsl,uart-has-rtscts;
status = "okay";
};
From imx6qdl-axelcommon.dtsi:
&iomuxc {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_hog_gpios>;
imx6ul-lynx {
...
...
pinctrl_uart2_flow: uart2grp-flow {
fsl,pins = <
MX6UL_PAD_UART2_TX_DATA__UART2_DCE_TX 0x1b0b1
MX6UL_PAD_UART2_RX_DATA__UART2_DCE_RX 0x1b0b1
MX6UL_PAD_UART2_CTS_B__UART2_DCE_CTS 0x1b0b1
MX6UL_PAD_UART2_RTS_B__UART2_DCE_RTS 0x1b0b1
>;
};
...
...
Accessing the peripheral[edit | edit source]
Linux messages at boot time[edit | edit source]
... ... [ 0.424294] 2020000.serial: ttymxc0 at MMIO 0x2020000 (irq = 21, base_baud = 5000000) is a IMX [ 1.125015] console [ttymxc0] enabled [ 1.130189] 2024000.serial: ttymxc7 at MMIO 0x2024000 (irq = 22, base_baud = 5000000) is a IMX [ 1.140851] 21e8000.serial: ttymxc1 at MMIO 0x21e8000 (irq = 58, base_baud = 5000000) is a IMX [ 1.150972] 21ec000.serial: ttymxc2 at MMIO 0x21ec000 (irq = 59, base_baud = 5000000) is a IMX ... ... root@imx6qxelk:~#
Usage with stty[edit | edit source]
N.B. UART mapping respect to ttymxcX is the following one:
UART1 <-> ttymxc0 UART2 <-> ttymxc1 UART3 <-> ttymxc2 UART4 <-> ttymxc3 UART5 <-> ttymxc4 UART6 <-> ttymxc5 UART7 <-> ttymxc6 UART8 <-> ttymxc7 ...
root@desk-mx6ul-axelulite:~# stty -F /dev/ttymxc7 115200 -echo root@desk-mx6ul-axelulite:~# cat /dev/ttymxc7 & [1] 331 root@desk-mx6ul-axelulite:~# echo "Test loopback" > /dev/ttymxc7 root@desk-mx6ul-axelulite:~#
Additional information[edit | edit source]
Serial ports can be used through the standard serial programming API.
For detailed information, please refer to the Serial Programming HOWTO at Serial-Programming-HOWTO
