AMIS-30623 Datasheet, PDF (42/65 Pages) AMI SEMICONDUCTOR – LIN Microstepping Motordriver

AMIS-30623
15.6 LIN Frames
The LIN frames can be divided in writing and reading frames. A frame is composed of an 8-bit Identifier followed by 2, 4 or 8 data-bytes.
Writing frames will be used to:
• Program the OTP Memory;
• Configure the component with the stepper-motor parameters (current, speed, stepping-mode, etc.);
• Provide set-point position for the stepper-motor.
Whereas reading frames will be used to:
• Get the actual position of the stepper-motor;
• Get status information such as error flags;
• Verify the right programming and configuration of the component.
15.6.1. Writing Frames
A writing frame is sent by the LIN master to send commands and/or information to the slave nodes. According to the LIN specification,
identifiers are to be used to determine a specific action. If a physical addressing is needed, then some bits of the data field can be
dedicated to this, as illustrated in the example below.
Identifier byte
Data byte 1
Data byte 2
ID0 ID1 ID2 ID3 ID4 ID5 ID6 ID7
phys. address
command parameters (e.g. position)
Another possibility is to determine the specific action within the data field in order to use less identifiers. One can for example use the
reserved identifier 0x3C and take advantage of the 8 byte data field to provide a physical address, a command and the needed
parameters for the action, as illustrated in the example below.
ID
Data1
Data2
0x3C 00
1
AppCmd command
Data3
physical
address
Data4
Data5
Data6
Data7
parameters
Data8
Note:
Bit 7 of byte Data1 must be at ‘1’ since the LIN specification requires that contents from 0x00 to 0x7F must be reserved for broadcast messages (0x00 being for the “Sleep”
message). See also LIN command Sleep
The writing frames used with the AMIS-30623 are the following:
• Type #1: General purpose 2 or 4 data bytes writing frame with a dynamically assigned identifier. This type is dedicated to
short writing actions when the bus load can be an issue. They are used to provide direct command to one (Broad =
‘1’) or all the slave nodes (Broad = ‘0’). If Broad = ‘1’, the physical address of the slave node is provided by the 7
remaining bits of DATA2. DATA1 will contain the command code (see Dynamic assignment of Identifiers), while, if
present, DATA3 to DATA4 will contain the command parameters, as shown below.
ID
ID0 ID1 ID2 ID3 ID4 ID5 ID6 ID7
Data1
command
Data2
Physical address Broad
Data3…
parameters…
• Type #2: 2, 4 or 8 data bytes writing frame with an identifier dynamically assigned to an application command, regardless of
the physical address of the circuit.
• Type #3: 2 data bytes writing frame with an identifier dynamically assigned to a particular slave node together with an
application command. This type of frame requires that there are as many dynamically assigned identifiers as there
are AMIS-30623 circuits using this command connected to the LIN bus.
• Type #4: 8 data bytes writing frame with 0x3C identifier.
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