32 lines
1.2 KiB
Plaintext
32 lines
1.2 KiB
Plaintext
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* RS485 serial communications
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The RTS signal is capable of automatically controlling line direction for
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the built-in half-duplex mode.
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The properties described hereafter shall be given to a half-duplex capable
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UART node.
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Optional properties:
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- rs485-rts-delay: prop-encoded-array <a b> where:
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* a is the delay between rts signal and beginning of data sent in milliseconds.
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it corresponds to the delay before sending data.
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* b is the delay between end of data sent and rts signal in milliseconds
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it corresponds to the delay after sending data and actual release of the line.
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If this property is not specified, <0 0> is assumed.
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- rs485-rts-active-low: drive RTS low when sending (default is high).
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- linux,rs485-enabled-at-boot-time: empty property telling to enable the rs485
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feature at boot time. It can be disabled later with proper ioctl.
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- rs485-rx-during-tx: empty property that enables the receiving of data even
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whilst sending data.
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RS485 example for Atmel USART:
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usart0: serial@fff8c000 {
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compatible = "atmel,at91sam9260-usart";
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reg = <0xfff8c000 0x4000>;
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interrupts = <7>;
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atmel,use-dma-rx;
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atmel,use-dma-tx;
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linux,rs485-enabled-at-boot-time;
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rs485-rts-delay = <0 200>; // in milliseconds
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};
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