Kontron SMARC-sAL28, Руководство пользователя

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SMARC-sAL28 User Guide. Rev. 1.0
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# gpiomon gpiochip4 7
8.2. UART
SMARC serial ports are enabled via UART ports on LS1028A SoC. Under Linux:
 SER0 maps to /dev/ttyLP0 Notes: RTS and CTS are available;
 SER1 maps to /dev/ttyS0 Notes: RX and TX only, Console port;
 SER3 maps to /dev/ttyS1 Notes: RX and TX only
LP-UART supports operation in half-duplex mode. For example, in case of KBox A-230-LS carrier board following
options can be configured via device tree:
 RS232:
&cpld_gpio1 {
rs485-gpio {
gpio-hog;
gpios = <0 GPIO_ACTIVE_HIGH>;
output-low;
};
rs232-gpio {
gpio-hog;
gpios = <1 GPIO_ACTIVE_HIGH>;
output-low;
};
};
&lpuart1 {
};
 RS485 half-duplex (2-wires):
&cpld_gpio1 {
rs485-gpio {
gpio-hog;
gpios = <0 GPIO_ACTIVE_HIGH>;
output-high;
};
rs232-gpio {
gpio-hog;
gpios = <1 GPIO_ACTIVE_HIGH>;
output-high;
};
};
&lpuart1 {
rs485,rts-low-polarity;
linux,rs485-enabled-at-boot-time;
};
 RS485 full-duplex (4-wires) :
&cpld_gpio1 {
rs485-gpio {
gpio-hog;
gpios = <0 GPIO_ACTIVE_HIGH>;
output-low;
};
rs232-gpio {
gpio-hog;
gpios = <1 GPIO_ACTIVE_HIGH>;
output-high;
};
};
&lpuart1 {
rs485,rts-low-polarity;
linux,rs485-enabled-at-boot-time;
};