TMC211 DATASHEET (V. 1.04 / January 7, 2005)
31
6.9.6 Reading Frames
When using reading frames the master initiates the communication by sending a header field, which
contains the synchronization and identifier field. The TMC211 supports two types of identifiers:
•
•
Direct ID: The identifier points to a particular slave node. As described in the LIN specification the
slave sends the data as in-frame response. Direct ID gives the fastest access to the required data.
Indirect ID: Indirect ID contains of two datagrams. The first datagram, called preparing frame,
issues the slave’s physical address to the particular slave node. The second datagram specifies
only a reading command by using the reserved identifier 0x3D. Indirect ID has the advantage to
use a reserved identifier and therefore provides more flexibility.
6.9.7 Reading Frame Type#5 (2, 4 or 8 bytes)
Type#5 is a reading frame, which uses a direct ID, therefore the master initiates the communication
and the slave responds after receiving the identifier. Dependent on the identifier the slave transmits 2,
4 or 8 bytes of data. GetActualPos command uses Type#5 reading frame.
ID
Master
ID [5:0] pp
Task
Dynamic
Identifier
Synch Break
Synch Field
In-Frame
Slave
Data1
Data2
Datax
Data8
Response
(2, 4 or 8 bytes)
Parameters back to master
6.9.8 Reading Frame Type#6 (8 bytes)
Reading frame Type#6 uses indirect ID and therefore a preparing frame of Type#7 or #8 is needed.
The preparing frame dumps the reading command into a particular slave node. Data from the slave is
then transmitted after the next reading frame. The reading frame must always be consecutive to a
preparing frame, otherwise it is not valid and not taken into account.
Master Task 1.
Preparing Frame Type#7 or Type#8
Master Task 2.
(Reading Frame)
ID
ID [7:0]
Identifier
Synch Break
Synch Field
0x3D
Slave
Data1
Data2
Datax
Data8
Response
(8 bytes)
Parameters back to master
Copyright © 2004-2005 TRINAMIC Motion Control GmbH & Co. KG
TRINAMIC [ TRINAMIC MOTION CONTROL GMBH & CO. KG. ]
