USB Interface
Overview
12Mbits/s bit rate
BC01 operates as a peripheral USB device
Two modes, bus powered and self powered
Careful product design is required for product to remain USB1.1 compliant
4 USB lines are required
Minimum voltage on VCC_IO terminal is 3.0V for USB operation
The SieMo contains its own
Although SieMo is capable of meeting the USB 1.1 specification, Siemens cannot guarantee that an application circuit designed around the IC is USB compliant. The choice of application circuit, component choice and PCB layout all affect USB signal quality and electrical characteristics. The information in this document is intended as a guide and should be read in association with the USB 1.1 specification, with particular attention being given to Chapter 7. Independent USB qualification must be sought before an application is deemed USB compliant and can bear the USB logo. Such qualification can be obtained from a USB plugfest or from an independent USB test house.
SieMo S50037 Data Book PRELIMINARILY
Disconnect and Resume Signalling
SieMo provides some signalling lines for USB operation. These functions are disabled by default but can be activated via firmware settings.
The USB_DETACH and USB_WAKE_UP terminals provide extra signalling alongside the normal USB data lines. They are not part of the USB specification and full USB functionality can be attained without their use. The Disconnect message may be useful on its own, but it is hard to see an application for USB_RESUME in isolation. USB_DETACH (Disconnect Signalling) USB_DETACH is an input, when asserted high, causes SieMo to put USB_PULL_UP, USB_D- and USB_D+ in
a
USB_RESUME
USB_WAKE_UP is an active high output used only when USB_DETACH is active to
Power Modes
SieMo is by default set to be powered from the Bus. It can be set to a self powered Device by changing firmware settings. In this case the USB_ON must be connected to the Vbus line via a 47k/22k
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