[etherlab-users] Sync manager and datagram react

[peak peak]

Hi,


So there's a possibility that the sync manager would react with datagrams that 
satisfy the length? A datagram not for the slave but with appropriate length may 
be supposed to be the datagram corresponding to that slave?

Best regards,



Hi 

>When reading the EtherCAT Master documentation about FMMU, I meet this sentence: 
>"In order to >make a sync manager react on a datagram accessing its memory, it 
>is necessary to access the last byte >covered by the sync manager." 
>

>I do not understand: which access to the last byte? Whose last byte? The last 
>byte in the datagram? or EtherCAT  frame?
The byte on the last address within the mailbox address range (see configured 
mailbox size) 


>How can sync manager identify its datagram by just the last byte?
By comparing the given address and the size of the transferred data.  A master 
must either write the full size of the mailbox (even if the real payload is much 
smaller) or it has to write 2 datagrams: One with the real payload, addressed to 
the start of the mailbox, and an additional datagram that writes just one byte 
at the end of the mailbox address range.

Regards, 
Martin
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