[etherlab-dev] Bandwidth optimizations

Florian Pose fp at igh-essen.com
Mon Jan 25 11:08:15 CET 2010


On Thu, Nov 05, 2009 at 02:36:05PM +0100, Daniel Bechter wrote:
> I realized that the EtherCAT-Master allocated 4 Bytes within the frame
> for the data. Isn't 2 Bytes enough? The ESC puts the output data from
> the LRW datagram with logical address 0x0 from Bit 0 to Bit 15 into
> the physical memory at 0x1100 and puts the input data from the
> physical memory at 0x1200 into the same area within the frame,
> effectively overwriting the output data with the input data.

this is really something, that could be implemented. We at IgH did not
break the bandwidth barrier by now ;-), for that we did'n have the need
for this. But, the functionality is also needed for direct slave-2-slave
communication. The basic idea is to program FMMUs read/write data at the
same address as another FMMU on the same, or on another slave. I'm not
really sure on how to include this in the current API. Do you have any

Best regards,
Florian Pose


More information about the etherlab-dev mailing list