COM20051 Datasheet, PDF (67/82 Pages) List of Unclassifed Manufacturers – Integrated Microcontroller and ARCNET (ANSI 878.1) Interface

initially timing the token rotation. In order to find
an existing ID to time the rotation, an 840ms
timer is used. At the end of the 840ms, the
DUPID is checked. If it is set then the node ID
value exists and can be used as a fake ID
(remember the node is not on the network). That
first ID value remains in the node ID register and
the above algorithm is used to determine the
remainder of the ID values.
EXNACK ISR
ISSUE DISABLE
TRANSMITTER
COMMAND
ISSUE CLEAR
FLAGS CMD.
FREE UP PAGE
IN TX_PEND REG
END
FIGURE 21 – EXCESSIVE NACK INTERRUPT SERVICE ROUTINE
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