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37 lines
804 B
37 lines
804 B
6 years ago
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# USART
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This unit provides access to the hardware USART peripheral. It is capable of
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driving RS485 transceivers.
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The unit uses asynchronous reception and transmission using DMA to support
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low baud rates without lagging the whole platform. Reception is double-buffered
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and sent in buffer-sized chunks. The remainder is sent when a timeout from
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the last received byte is reached.
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## Commands
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### WRITE (0x00)
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Add data to the Tx buffer. Sending is asynchronous, but the command may wait
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for free space in the DMA buffer.
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*Request:*
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- u8[] - bytes to write
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### WRITE_SYNC (0x01)
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Add data to the Tx buffer and wait for the transmission to complete.
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*Request:*
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- u8[] - bytes to write
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## Events
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### DATA_RECEIVED (0x00)
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Data was received on the serial port.
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*Payload:*
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- u8[] - received bytes
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