Kontron USB-16REL, User Manual

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USB-16REL User’s Guide
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Serial String
Each device has an eight digit alphanumeric serial string stored in non-volatile memory. On
Windows platforms, this number is used to give each unit a separate identity. This identity allows
the device to be moved to any USB port or hub port on your computer while retaining its device
number. If a device becomes damaged and is replaced the new device should be given the same
serial string as the device it is replacing.
This string is stored in an EEPROM along with other critical information. This EEPROM is read
during enumeration. The device should not be unplugged during its enumeration due to a
remote possibility that the data in the EEPROM could be corrupted if power is removed during a
read/write cycle.
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Relative Addressing vs. Absolute
Addressing
The SeaI/O API makes a distinction between “absolute” and “relative” addressing modes. In
absolute addressing mode, the Port argument to the API function acts as a simple byte offset
from the base I/O address of the device. For instance, Port #0 refers to the I/O 0; Port #1 refers
to the I/O address 1.
Relative addressing mode, on the other hand, refers to input and output ports in a logical
fashion. With a Port argument of 0 and an API function meant to output data, the first (0th)
output port on the device will be utilized. Likewise, with a Port argument of 0 and an API function
designed to input data, the first (0th) input port of the device will be utilized.
In all addressing modes, port numbers are zero-indexed; that is, the first port is port #0, the
second port is #1, the third #2, and so on.
Important: The control panel utility provides the capability to read or modify this
string. However, setting the same string for two units will cause the second unit to
fail enumeration and make it invisible to the operating system. Should this occur,
unplug one unit and set the serial string for the other unit to a different string.