Intel 8XC196Lx Benutzerhandbuch
8XC196L
X SUPPLEMENT
8-8
of arbitration, nodes A, C, and D are all transmitting an “active 0” symbol, thus the idle state of
the “passive 1” symbol is overruled in favor of the driven state of the “active 0” symbol.
the “passive 1” symbol is overruled in favor of the driven state of the “active 0” symbol.
Node C is the next node to discontinue transmitting when it attempts to take control of the bus by
transmitting an “active 1” symbol. However, nodes A and D maintain control by continuing to
drive the bus with an “active 0” symbol.
transmitting an “active 1” symbol. However, nodes A and D maintain control by continuing to
drive the bus with an “active 0” symbol.
Finally, node D discontinues transmitting when its attempt to hold the bus in an idle state is over-
ruled by the driven state of the “active 1” symbol on node A. Thus, node A is awarded arbitration.
ruled by the driven state of the “active 1” symbol on node A. Thus, node A is awarded arbitration.
The busline signal, detected on the bus by the receiver, reflects node A’s message, as this is the
only node that did not experience contention.
only node that did not experience contention.
Figure 8-5. Bit Arbitration Example
8.4
MESSAGE FRAMES
A message transmission or reception is transferred within a message frame that adds control and
error-detection bits to the content of the message. The frame for an IFR message differs slightly
from that for a standard message, but they contain similar information (Figure 8-6).
error-detection bits to the content of the message. The frame for an IFR message differs slightly
from that for a standard message, but they contain similar information (Figure 8-6).
A5223-01
Node B
"0"
"0"
"0"
"1"
"0"
"1"
Node C
"0"
"0"
"0"
"1"
"0"
"1"
"0"
Node D
Busline
"0"
"0"
"0"
"0"
"0"
"1"
"0"
"1"
"0"
"0"
Node A
Point of
Arbitration
Arbitration
"1"
Point of
Arbitration
Arbitration
Point of
Arbitration
Arbitration