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(UART naming under Linux)
 
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= {{#var:HARDWARE_NAME}} UART Overview =
 
= {{#var:HARDWARE_NAME}} UART Overview =
 
{{#ifeq: {{#var:HARDWARE_NAME}} | VAR-SOM-MX8X |
 
{{#ifeq: {{#var:HARDWARE_NAME}} | VAR-SOM-MX8X |
On VAR-SOM-MX8X up to 4 UARTS can be used. All 4 UARTs on {{#var:HARDWARE_NAME}} are enabled by default.<br>
+
On VAR-SOM-MX8X up to 4 UARTS can be used.<br>
UART3 is used as for debug console, UART0,UART1,UART2 are connected to J18 header on Symphony-Board.<br>
+
All 4 UARTs are enabled by default.<br>
 +
UART3 is used as for debug console, UART0, UART1 and UART2 are connected to J18 header on Symphony-Board.<br>
 
UART0 is connected to Bluetooth module on SOM, it can be used on J18 only when BT is disabled.<br>
 
UART0 is connected to Bluetooth module on SOM, it can be used on J18 only when BT is disabled.<br>
Only UART0,UART1 have RTS and CTS lines.
+
Only UART0, UART1 have RTS and CTS lines.
 
Inspect the carrier board datasheet or schematics for the exact pinout.<br>  
 
Inspect the carrier board datasheet or schematics for the exact pinout.<br>  
 
|
 
|
On VAR-SOM-MX8 up to 5 UARTS can be used. UART0,UART1,UART2,UART4 are enabled, UART3 is disabled as it shares pins with the second Ethernet controller, UART5 is not defined.<br>
+
'''On VAR-SOM-MX8''' up to 5 UARTS can be used.<br>
UART0 is used for debug console, UART1,UART2,UART4 are connected to J18 header on Symphony-Board, UART3 is connected to J30 header on Symphony-Board (not assembled by default).<br>
+
By default, UART0, UART1, UART2 and UART4 are enabled, UART3 is disabled as it shares pins with the second Ethernet controller. UART5 is not defined.<br>
 +
UART0 is used for debug console, UART1, UART2 and UART4 are connected to J18 header on Symphony-Board. UART3 is connected to J30 header on Symphony-Board (not assembled by default).<br>
 
UART1 is connected to Bluetooth module on SOM, it can be used on J18 only when BT is disabled.<br>
 
UART1 is connected to Bluetooth module on SOM, it can be used on J18 only when BT is disabled.<br>
Only UART0,UART1,UART3 have RTS and CTS lines.<br>
+
Only UART0, UART1 and UART3 have RTS and CTS lines.<br>
 
Inspect the carrier board datasheet or schematics for the exact pinout.<br>  
 
Inspect the carrier board datasheet or schematics for the exact pinout.<br>  
 
+
<br>
On SPEAR-MX8 up to 5 UARTS can be used. UART0,UART1,UART2 are enabled, UART3,UART4 are not defined (UART3 shares pins with the second Ethernet controller).<br>
+
'''On SPEAR-MX8''' up to 5 UARTS can be used.<br>
UART0 is used for debug console, UART0,UART2 are connected to J26 header on SPEAR-CustomBoard, UART3,UART4 are connected to J20 header on on SPEAR-CustomBoard .<br>
+
By default, UART0, UART1 and UART2 are enabled, and UART3 and UART4 are not defined (UART3 shares pins with the second Ethernet controller).<br>
UART1 is connected to Bluetooth module on SOM, it can be used only when BT is disabled (not exported on SPEAR-CustomBoard) .<br>
+
UART0 is used for debug console, UART0 and UART2 are connected to J26 header on SPEAR-CustomBoard. UART3 and UART4 are connected to J20 header on the SPEAR-CustomBoard.<br>
Only UART0,UART1,UART3 have RTS and CTS lines.<br>
+
UART1 is connected to the Bluetooth module on the SOM. it can be used only when BT is disabled (not exported on SPEAR-CustomBoard).<br>
 +
Only UART0, UART1 and UART3 have RTS and CTS lines.<br>
 
Inspect the carrier board datasheet or schematics for the exact pinout.<br>  
 
Inspect the carrier board datasheet or schematics for the exact pinout.<br>  
 
}}
 
}}
 +
 
= UART naming under Linux =
 
= UART naming under Linux =
  
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Short J18.3 and J18.5 pins and run the following commands:
 
Short J18.3 and J18.5 pins and run the following commands:
 
<pre>
 
<pre>
stty -F /dev/ttyLP1 -echo -onlcr 115200
+
# stty -F /dev/ttyLP1 -echo -onlcr 115200
cat /dev/ttyLP1 &
+
# cat /dev/ttyLP1 &
echo hello > /dev/ttyLP1
+
# echo hello > /dev/ttyLP1
 
</pre>
 
</pre>
  
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Short J18.7 and J18.9 pins and run the following commands:
 
Short J18.7 and J18.9 pins and run the following commands:
 
<pre>
 
<pre>
stty -F /dev/ttyLP2 -echo -onlcr 115200
+
# stty -F /dev/ttyLP2 -echo -onlcr 115200
cat /dev/ttyLP2 &
+
# cat /dev/ttyLP2 &
echo hello > /dev/ttyLP2
+
# echo hello > /dev/ttyLP2
 
</pre>
 
</pre>
  
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Short J18.3 and J18.5 pins and run the following commands:
 
Short J18.3 and J18.5 pins and run the following commands:
 
<pre>
 
<pre>
stty -F /dev/ttyLP2 -echo -onlcr 115200
+
# stty -F /dev/ttyLP2 -echo -onlcr 115200
cat /dev/ttyLP2 &
+
# cat /dev/ttyLP2 &
echo hello > /dev/ttyLP2
+
# echo hello > /dev/ttyLP2
 
</pre>
 
</pre>
  
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Short J18.7 and J18.9 pins and run the following commands:
 
Short J18.7 and J18.9 pins and run the following commands:
 
<pre>
 
<pre>
stty -F /dev/ttyLP4 -echo -onlcr 115200
+
# stty -F /dev/ttyLP4 -echo -onlcr 115200
cat /dev/ttyLP4 &
+
# cat /dev/ttyLP4 &
echo hello > /dev/ttyLP4
+
# echo hello > /dev/ttyLP4
 
</pre>
 
</pre>
  
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Short J26.17 and J26.19 pins and run the following commands:
 
Short J26.17 and J26.19 pins and run the following commands:
 
<pre>
 
<pre>
stty -F /dev/ttyLP2 -echo -onlcr 115200
+
# stty -F /dev/ttyLP2 -echo -onlcr 115200
cat /dev/ttyLP2 &
+
# cat /dev/ttyLP2 &
echo hello > /dev/ttyLP2
+
# echo hello > /dev/ttyLP2
 
</pre>
 
</pre>
  
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|
 
|
 
= Disabling UART2 =
 
= Disabling UART2 =
To disable UART2 on VAR-SOM-MX8 edit arch/arm64/boot/dts/freescale/fsl-imx8qxp-var-som-common.dtsi under kernel source directory and modify
+
To disable UART2 '''on VAR-SOM-MX8''' edit arch/arm64/boot/dts/freescale/fsl-imx8qxp-var-som-common.dtsi under kernel source directory and modify
  
 
<pre>
 
<pre>
Line 124: Line 128:
 
};
 
};
 
</pre>
 
</pre>
 
+
<br>
<br> On SPEAR-MX8 modify arch/arm64/boot/dts/freescale/fsl-imx8qxp-var-spear-common.dtsi in the same manner.
+
'''On SPEAR-MX8''' modify arch/arm64/boot/dts/freescale/fsl-imx8qxp-var-spear-common.dtsi in the same manner.
 
}}
 
}}

Latest revision as of 05:48, 1 December 2019

UART


1 UART Overview

On VAR-SOM-MX8 up to 5 UARTS can be used.
By default, UART0, UART1, UART2 and UART4 are enabled, UART3 is disabled as it shares pins with the second Ethernet controller. UART5 is not defined.
UART0 is used for debug console, UART1, UART2 and UART4 are connected to J18 header on Symphony-Board. UART3 is connected to J30 header on Symphony-Board (not assembled by default).
UART1 is connected to Bluetooth module on SOM, it can be used on J18 only when BT is disabled.
Only UART0, UART1 and UART3 have RTS and CTS lines.
Inspect the carrier board datasheet or schematics for the exact pinout.

On SPEAR-MX8 up to 5 UARTS can be used.
By default, UART0, UART1 and UART2 are enabled, and UART3 and UART4 are not defined (UART3 shares pins with the second Ethernet controller).
UART0 is used for debug console, UART0 and UART2 are connected to J26 header on SPEAR-CustomBoard. UART3 and UART4 are connected to J20 header on the SPEAR-CustomBoard.
UART1 is connected to the Bluetooth module on the SOM. it can be used only when BT is disabled (not exported on SPEAR-CustomBoard).
Only UART0, UART1 and UART3 have RTS and CTS lines.
Inspect the carrier board datasheet or schematics for the exact pinout.

2 UART naming under Linux

The Linux devices corresponding to UART0 - UART4 are /dev/ttyLP0 - /dev/ttyLP4 respectively.

3 Testing UART2 on VAR-SOM-MX8

Short J18.3 and J18.5 pins and run the following commands:

# stty -F /dev/ttyLP2 -echo -onlcr 115200
# cat /dev/ttyLP2 &
# echo hello > /dev/ttyLP2

For each invocation of echo command the "hello" string should appear on the terminal.

4 Testing UART4 on VAR-SOM-MX8

Short J18.7 and J18.9 pins and run the following commands:

# stty -F /dev/ttyLP4 -echo -onlcr 115200
# cat /dev/ttyLP4 &
# echo hello > /dev/ttyLP4

5 Testing UART2 on SPEAR-MX8

Short J26.17 and J26.19 pins and run the following commands:

# stty -F /dev/ttyLP2 -echo -onlcr 115200
# cat /dev/ttyLP2 &
# echo hello > /dev/ttyLP2

For each invocation of echo command the "hello" string should appear on the terminal.

6 Disabling UART2

To disable UART2 on VAR-SOM-MX8 edit arch/arm64/boot/dts/freescale/fsl-imx8qxp-var-som-common.dtsi under kernel source directory and modify

&lpuart2 {
        ...
        status = "okay";
};

to

&lpuart2 {
        ...
        status = "disabled";
};


On SPEAR-MX8 modify arch/arm64/boot/dts/freescale/fsl-imx8qxp-var-spear-common.dtsi in the same manner.