Difference between revisions of "DESK-MX8M-L/Peripherals/UART"
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=== Device tree configuration === | === Device tree configuration === | ||
| − | Here below an example of device tree | + | Here below an example of device tree modifications to standard DAVE's kit for the ORCA SOM: |
From <code>imx8mp-mito8mplus.dtsi</code>: | From <code>imx8mp-mito8mplus.dtsi</code>: | ||
<pre> | <pre> | ||
| − | & | + | &uart4 { |
| − | + | pinctrl-names = "default"; | |
| − | + | pinctrl-0 = <&pinctrl_uart4>; | |
| − | + | assigned-clocks = <&clk IMX8MP_CLK_UART4>; | |
| + | assigned-clock-parents = <&clk IMX8MP_SYS_PLL1_80M>; | ||
| + | fsl,uart-has-rtscts; | ||
| + | status = "okay"; | ||
}; | }; | ||
&iomuxc { | &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 | |
| + | >; | ||
| + | }; | ||
| + | |||
</pre> | </pre> | ||
| Line 49: | Line 53: | ||
... | ... | ||
... | ... | ||
| − | [ 0. | + | [ 0.755511] 30860000.serial: ttymxc0 at MMIO 0x30860000 (irq = 26, base_baud = 5000000) is a IMX |
| − | [ 0. | + | [ 0.762356] 30880000.serial: ttymxc2 at MMIO 0x30880000 (irq = 27, base_baud = 5000000) is a IMX |
| − | [ 0. | + | [ 0.771151] 30890000.serial: ttymxc1 at MMIO 0x30890000 (irq = 28, base_baud = 1500000) is a IMX |
| + | [ 0.779648] printk: console [ttymxc1] enabled | ||
| + | [ 0.798672] 30a60000.serial: ttymxc3 at MMIO 0x30a60000 (irq = 35, base_baud = 5000000) is a IMX | ||
... | ... | ||
... | ... | ||
| Line 67: | Line 73: | ||
<pre class="workstation-terminal"> | <pre class="workstation-terminal"> | ||
| − | root@desk-mx8mp:~# stty -F /dev/ | + | root@desk-mx8mp:~# stty -F /dev/ttymxc3 115200 -echo |
| − | root@desk-mx8mp:~# cat /dev/ | + | root@desk-mx8mp:~# cat /dev/ttymxc3 & |
[2] 555 | [2] 555 | ||
| − | root@desk-mx8mp:~# echo "Test loopback" > /dev/ | + | root@desk-mx8mp:~# echo "Test loopback" > /dev/ttymxc3 |
root@desk-mx8mp:~# Test loopback | root@desk-mx8mp:~# Test loopback | ||
</pre> | </pre> | ||
Revision as of 14:15, 30 December 2021
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| Version | Issue Date | Notes | |
| 1.0.0 | Jan 2022 | First DESK-MX8M release | |
Contents
Peripheral UART[edit | edit source]
Device tree configuration[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>;
assigned-clocks = <&clk IMX8MP_CLK_UART4>;
assigned-clock-parents = <&clk IMX8MP_SYS_PLL1_80M>;
fsl,uart-has-rtscts;
status = "okay";
};
&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
>;
};
Accessing the peripheral[edit | edit source]
Linux messages at boot time[edit | edit source]
... ... [ 0.755511] 30860000.serial: ttymxc0 at MMIO 0x30860000 (irq = 26, base_baud = 5000000) is a IMX [ 0.762356] 30880000.serial: ttymxc2 at MMIO 0x30880000 (irq = 27, base_baud = 5000000) is a IMX [ 0.771151] 30890000.serial: ttymxc1 at MMIO 0x30890000 (irq = 28, base_baud = 1500000) is a IMX [ 0.779648] printk: console [ttymxc1] enabled [ 0.798672] 30a60000.serial: ttymxc3 at MMIO 0x30a60000 (irq = 35, base_baud = 5000000) is a IMX ... ... root@desk-mx8mp:~#
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 ...
root@desk-mx8mp:~# stty -F /dev/ttymxc3 115200 -echo root@desk-mx8mp:~# cat /dev/ttymxc3 & [2] 555 root@desk-mx8mp:~# echo "Test loopback" > /dev/ttymxc3 root@desk-mx8mp:~# Test loopback
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
