vault backup: 2025-08-03 13:41:47
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10
notes/USB.md
10
notes/USB.md
@ -12,4 +12,12 @@ USB devices are one of the following:
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# Interconnects
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# Protocol
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A Universal Serial bus is strictly a *polled* bus, meaning the
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A Universal Serial bus is strictly a *polled* bus, meaning the host controller initiates every data transfer.
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Most bus transactions involve the transmission of up to three packets.
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1. The token packet
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> Each transaction begins when the host, on a scheduled basis, sends a USB packet describing the type and direction of a transaction, the USB device address, and endpoint number.
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2. The data packet
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> Depending on the di
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3. The handshake packet
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> The destination, in general, responds to a handshake packet indicating whether the transfer was successful.
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