vault backup: 2025-08-03 13:36:47

notes/USB.md

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+A USB system is composed of three areas:
+- USB interconnect (cables, ports)
+- USB devices (keyboard, storage, controller)
+- USB host (Laptop, computer)
+
+# Hosts
+There is only one host in any USB system. The USB interface to the host computer is referred to as the Host Controller. The Host Controller may be implemented in a combination of hardware, firmware, or software. A root hub is integrated within the host system to provide one or more attachment points.
+# Devices
+USB devices are one of the following:
+- A hub, providing additional attachment points to the bus
+- Functions that provide capabilities to the system (speakers, keyboard)
+# Interconnects
+
+# Protocol
+A Universal Serial bus is strictly a *polled* bus, meaning the