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TC1784
FlexRay™ Protocol Controller (E-Ray)
User´s Manual
20-214
V1.1, 2011-05
E-Ray, V3.13
The startup noise timer is restarted upon:
•
Entering the “COLDSTART_LISTEN” state
•
Reception of correctly decoded Headers or CAS symbols while the node is in
“COLDSTART_LISTEN” state
The startup noise timer is stopped when the “COLDSTART_LISTEN” state is left.
Once the startup noise time-out expires, neither an overflow nor a cyclic restart of the
timer is performed. The status is kept for further processing by the startup state machine.
Since the startup noise timer won’t be restarted when random channel activity is sensed,
this time-out defines the fall-back solution that guarantees that a node will try to start up
the communication cluster even in the presence of noise.
20.6.5.8 Path of leading Coldstart Node (initiating coldstart)
When a coldstart node enters “COLDSTART_LISTEN”, it listens to its attached
channels.
If no communication is detected, the node enters the “COLDSTART_COLLISION_
RESOLUTION” state and commences a coldstart attempt. The initial transmission of a
CAS symbol is succeeded by the first regular cycle. This cycle has the number zero.
From cycle zero on, the node transmits its startup Frame. Since each coldstart node is
allowed to perform a coldstart attempt, it may occur that several nodes simultaneously
transmit the CAS symbol and enter the coldstart path. This situation is resolved during
the first four cycles after CAS transmission.
As soon as a node that initiates a coldstart attempt receives a CAS symbol or a Frame
Header during these four cycles, it re-enters the “COLDSTART_LISTEN” state. Thereby,
only one node remains in this path. In cycle four, other coldstart nodes begin to transmit
their startup Frames.
After four cycles in “COLDSTART_COLLISION_RESOLUTION” state, the node that
initiated the coldstart enters the “COLDSTART_CONSISTENCY_CHECK” state. It
collects all startup Frames from cycle four and five and performs the clock correction. If
the clock correction does not deliver any errors and it has received at least one valid
Startup Frame pair, the node leaves “COLDSTART_CONSISTENCY_CHECK” and
enters “NORMAL_ACTIVE” state.
The number of coldstart attempts that a node is allowed to perform is configured by
in the SUC Configuration Register 1. The number of remaining coldstarts
attempts
can be read from Communication Controller Status Vector
register. The number of remaining attempts is reduced by one for each attempted
coldstart. A node may enter the “COLDSTART_LISTEN” state only if this value is larger
than one and it may enter the “COLDSTART_COLLISION_RESOLUTION” state only if
this value is larger than zero. If the number of coldstart attempts is one, coldstart is
inhibited but integration is still possible.
Summary of Contents for TC1784
Page 1: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Page 3: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Page 950: ...TC1784 Direct Memory Access Controller DMA User s Manual 11 132 V1 1 2011 05 DMA V3 03 ...
Page 1949: ...TC1784 General Purpose Timer Array GPTA v5 User s Manual 21 297 V1 1 2011 05 GPTA v5 V1 14 ...
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