DESK-MX8M-L/Peripherals/UART
| HOME | SOMs | SBCs | ToloMEO Embedded Assistant |  GET A QUOTE
|
 ONLINE HELPDESK
|
| Roadmap | IoT Services | ML/AI services | Embedded Design Services |
| History | |||
|---|---|---|---|
| Issue Date | Notes | ||
| First DESK-MX8M-L release | |||
| DESK-MX8M-L-2.0.0 release | |||
| DESK-MX8M-L-4.0.0 release | |||
| 2024/04/11 | DESK-MX8M-L-4.1.0 release | ||
Contents
Peripheral UART[edit | edit source]
Device tree configuration[edit | edit source]
ORCA SOM[edit | edit source]
Here below an example of device tree modifications to standard DAVE's kit for the ORCA SOM:
From imx8mp-mito8mplus.dtsi:
...
...
&uart4 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart4_j8>;
assigned-clocks = <&clk IMX8MP_CLK_UART4>;
assigned-clock-parents = <&clk IMX8MP_SYS_PLL1_80M>;
/*fsl,uart-has-rtscts;*/
status = "disabled";
};
...
...
&iomuxc {
...
...
pinctrl_uart4: uart4grp {
fsl,pins = <
MX8MP_IOMUXC_ECSPI2_SCLK__UART4_DCE_RX 0x140
MX8MP_IOMUXC_ECSPI2_MOSI__UART4_DCE_TX 0x140
MX8MP_IOMUXC_ECSPI2_MISO__UART4_DCE_CTS 0x140
MX8MP_IOMUXC_ECSPI2_SS0__UART4_DCE_RTS 0x140
>;
};
pinctrl_uart4_j8: uart4grp {
fsl,pins = <
MX8MP_IOMUXC_UART4_TXD__UART4_DCE_TX 0x140
MX8MP_IOMUXC_UART4_RXD__UART4_DCE_RX 0x140
>;
};
...
MITO 8M Mini[edit | edit source]
Here below an example of device tree configuration used on standard DAVE's kit for the MITO 8M Mini SOM:
From imx8mm-mito8mmini.dtsi:
...
...
&uart1 {
assigned-clocks = <&clk IMX8MM_CLK_UART1>;
assigned-clock-parents = <&clk IMX8MM_SYS_PLL1_80M>;
status = "disabled";
};
...
...
&iomuxc {
...
...
pinctrl_uart1: uart1grp {
fsl,pins = <
MX8MM_IOMUXC_UART1_RXD_UART1_DCE_RX 0x140
MX8MM_IOMUXC_UART1_TXD_UART1_DCE_TX 0x140
MX8MM_IOMUXC_UART3_RXD_UART1_DCE_CTS_B 0x140
MX8MM_IOMUXC_UART3_TXD_UART1_DCE_RTS_B 0x140
>;
};
...
...
From imx8mm-mito8mmini-sbcx.dts:
...
...
/ {
regulators: regulators {
...
...
/* enable ISL3330IAZ on SBCX at boot */
reg_uart1_en: uart1_en {
compatible = "regulator-fixed";
regulator-name = "uart1_en";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart1_en>;
regulator-min-microvolt = <3300000>;
regulator-max-microvolt = <3300000>;
gpio = <&gpio3 24 GPIO_ACTIVE_HIGH>;
enable-active-high;
regulator-always-on;
regulator-boot-on;
};
...
...
};
};
...
...
&uart1 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart1>;
fsl,uart-has-rtscts;
status = "okay";
};
...
...
&iomuxc {
...
...
pinctrl_uart1_en: uart1_en {
fsl,pins = <
MX8MM_IOMUXC_SAI5_RXD3_GPIO3_IO24 0x19
>;
};
...
...
Accessing the peripheral in ORCA SOM[edit | edit source]
Linux messages at boot time[edit | edit source]
... ... [ 0.836042] 30860000.serial: ttymxc0 at MMIO 0x30860000 (irq = 31, base_baud = 5000000) is a IMX [ 0.843116] 30880000.serial: ttymxc2 at MMIO 0x30880000 (irq = 32, base_baud = 5000000) is a IMX [ 0.851863] 30890000.serial: ttymxc1 at MMIO 0x30890000 (irq = 33, base_baud = 1500000) is a IMX [ 0.860354] printk: console [ttymxc1] enabled ... ...
Usage with stty[edit | edit source]
N.B. UART mapping respect to ttymxcX is the following one:
UART1 (RS232) <-> ttymxc0 UART2 (Serial Port) <-> ttymxc1 UART3 (UART) <-> ttymxc2 UART4 (RS485) <-> ttymxc3 ...
root@desk-mx8mp:~# stty -F /dev/ttymxc0 115200 -echo -raw root@desk-mx8mp:~# cat /dev/ttymxc0 > test_ttymxc0.log & [1] 1868 root@desk-mx8mp:~# echo "Test loopback" > /dev/ttymxc0 root@desk-mx8mp:~# cat test_ttymxc0.log Test loopback root@desk-mx8mp:~#
Accessing the peripheral in MITO 8M Mini[edit | edit source]
Linux messages at boot time[edit | edit source]
... ... [ 0.812632] 30860000.serial: ttymxc0 at MMIO 0x30860000 (irq = 40, base_baud = 5000000) is a IMX [ 0.860368] 30890000.serial: ttymxc1 at MMIO 0x30890000 (irq = 42, base_baud = 1500000) is a IMX [ 0.869035] printk: console [ttymxc1] enabled ... ...
Usage with stty[edit | edit source]
N.B. UART mapping respect to ttymxcX is the following one:
UART1 (RS232/RS485/RS422 port DB9) <-> ttymxc0 UART2 (Serial Port) <-> ttymxc1 UART3 (PMOD) <-> ttymxc2 UART4 (UART for Cortex-M4) <-> ttymxc3 ...
root@desk-mx8mm:~# dmesg | grep tty^C root@desk-mx8mm:~# stty -F /dev/ttymxc0 115200 -echo -raw root@desk-mx8mm:~# cat /dev/ttymxc0 > test_ttymxc0.log & [1] 1313 root@desk-mx8mm:~# echo "Test loopback" > /dev/ttymxc0 root@desk-mx8mm:~# cat test_ttymxc0.log Test loopback root@desk-mx8mm:~#
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
