AMIS-30623 LIN Microstepping Motordriver
Data Sheet
16.6.4. Dynamic Assignment of Identifiers
The identifier field in the LIN datagram denotes the content of the message. Six identifier bits and two parity bits are used to represent
the content. The identifiers 0x3C and 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 the identifiers will fulfill 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 will write 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] place the corresponding dynamic identifier Dyn_ID_x [5:0] at the correct place in the RAM (see Table 1: LIN – Dynamic
Identifiers Writing Frame).
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
Bit 4 Bit 3
Bit 7
Bit 6
Bit 5
Bit 2
Bit 1
Bit 0
0
1
2
3
4
5
6
7
8
Identifier
AppCmnd
CMD
Address
Data
Data
Data
Data
Data
0x3C
0x80
1
0x11
AD3
Broad
AD6
AD5
AD4
AD2
AD1
AD0
DynID_1[3:0]
DynID_2[1:0]
ROMp_3[3:0]
ROMp_4[2:0]
ROMp_1[3:0]
DynID_1[5:4]
DynID_2[5:2]
DynID_3[5:0]
ROMp_2[3:0]
DynID_4[5:0]
ROMp_4[3:2]
Where:
CMD[6:0]:
Broad:
0x11, corresponding to dynamic assignment of four LIN identifiers
If broad = ‘0’ all the circuits connected to the LIN bus will share the same dynamically assigned
identifiers.
DynID_x[5:0]: Dynamically assigned LIN identifier to the application command which ROM pointer is ROMp_x[3:0]
One frame allows only to assign four identifiers. Therefore, additional frames could be needed in order to assign more identifiers
(maximum three for the AMIS-30623).
Dynamic ID
ROM pointer
Application Command
User Defined
0010
GetActualPos
User Defined
User Defined
User Defined
User Defined
User Defined
User Defined
User Defined
User Defined
User Defined
0011
0100
0101
0110
0111
0000
0001
1000
1001
GetStatus
SetPosition
SetPositionShort (1 m)
SetPositionShort (2 m)
SetPositionShort (4 m)
GeneralPurpose 2 bytes
GeneralPurpose 4bytes
Preparation Frame
SetPosParam
Command assignement done at start-up
Command assignement via Dynamic ID during operation
Figure 26:Principle of Dynamic Command Assignment
AMI Semiconductor – June 2006, Rev 3.0
46
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