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TMC211 DATASHEET (V. 1.04 / January 7, 2005)
6.8 Dynamic Assignment of LIN Identifiers
The identifier field in the LIN message frame denotes the content of the message. Six identifier bits
and two parity bits are used to represent the content. The identifiers 0x3C to 0x3F are reserved for
command frames and extended frames. Slave nodes need to be very flexible to adapt itself to a given
LIN network in order to avoid conflicts with slave nodes from different manufacturers. Dynamic
assignment of identifiers fulfills this requirement by writing identifiers into the circuits RAM. ROM
pointers are linking commands and dynamic identifiers together.
A writing frame with identifier 0x3C issued by the LIN master writes dynamic identifiers into the RAM.
One writing frame is able to assign 4 identifiers, therefore 3 frames are needed to assign all identifiers.
Each ROM pointer ROMp_x [3:0] places the corresponding dynamic identifier Dyn_ID_x [5:0] at the
correct place in the RAM, see table below. When setting <BROAD> to zero broadcasting is active and
each slave on the LIN bus will store the same dynamic identifiers, otherwise only the slave with the
corresponding slave address is programmed.
Dynamic Identifiers Writing Frame
Byte
Content
Structure
Bit3
Bit7
Bit6
Bit5
Bit4
Bit2
Bit1
Bit0
0
1
2
3
4
5
6
7
8
Identifier
AppCMD
CMD
0x3C
0x80
1
0x11
AD3
Address
Data
Broad
AD6
AD5
AD4
AD2
ROMp_1 [3:0]
DynID_1 [5:4]
DynID_2 [5:2]
AD1
AD0
DynID_1 [3:0]
Data
DynID_2 [1:0]
ROMp_3 [3:0]
ROMp_4 [1:0]
ROMp_2 [3:0]
Data
Data
DynID_3 [5:0]
Data
DynID_4 [5:0]
ROMp_4 [3:2]
ROM pointer
Dynamic ID
Application command
(binary)
0000
0001
0010
0011
0100
0101
0110
0111
1000
user defined
user defined
user defined
user defined
user defined
user defined
user defined
user defined
user defined
General purpose 2 data bytes
General purpose 4 data bytes
GetActualPosition
GetStatus
SetPosition (2 data bytes)
SetPositionShort (1 Motor)
SetPositionShort (2 Motors)
SetPositionShort (4 Motors)
Preparation frame
Dynamic assignment done at start-up
Command assignment via Dynamic ID during operation
Figure 17: Principle of dynamic command assignment
Copyright © 2004-2005 TRINAMIC Motion Control GmbH & Co. KG
TRINAMIC [ TRINAMIC MOTION CONTROL GMBH & CO. KG. ]
