DS2490 View Datasheet(PDF) - Dallas Semiconductor -> Maxim Integrated
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Description
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DS2490 Datasheet PDF : 50 Pages
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STRONG PULLUP TO 5V, PREDEFINED DURATION Figure 8
DS2490
12V PROGRAMMING PULSE, PREDEFINED DURATION Figure 9
USB COMMUNICATION
Communication with the DS2490 is performed using USB standard requests, also referred to as core
commands or requests in this document, and DS2490 vendor specific USB commands. All command
communication with the DS2490 is performed over the default control pipe. Non-command
communication, including 1-Wire device data I/O and DS2490 status information, occurs in a vendor-
specific fashion over bulk and interrupt pipes. Configuration of the DS2490 USB controller is shown in
Figure 10. As shown, a Dallas Semiconductor vendor-specific 1-Wire device exists with a single 1-Wire
interface. The USB vendor-specific 1-Wire function of the DS2490 will be implemented and controlled
by the device driver at the device level of the device class hierarchy, i.e, vendor-specific commands will
be directed to the device level. Within the 1-Wire interface, four endpoints exist to control and
communicate with the device. Four alternate settings of the 1-Wire interface exist which correspond to
different operating modes for the endpoints. Endpoint and interface descriptions are summarized in the
following paragraphs.
The DS2490 provides USB remote wakeup capability. Per the USB specification, if a device supports
remote wakeup, it must also provide the ability to enable or disable the remote wakeup function. In
addition, the remote wakeup feature must be disabled as the power up default or device reset state. When
the remote wakeup feature is enabled, the DS2490 will send USB resume signaling to a suspended host
system upon detecting a 1-Wire device attachment. It then becomes the responsibility of host system
software to resume operation and to determine what servicing is required for the 1-Wire device.
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