On 12 August 2011 16:56, cogoman <[email protected]> wrote: > What is the sequence of messages sent and received to an FPGA parallel > port servo card at each servo interval? I looked on the wiki and > couldn't find this information. What all goes on when controlling 3 > servos over the parallel port?
Are you talking about the Mesa 7i43 specifically, or is the question more generic? if you are talking about the 7i43, then there are a number of 32-bit registers associated with each Hostmot2 function. The data and/or settings for the functions are encoded in these registers. During the hm7o43_read cycle the driver asks for the values in the registers (2 bytes of address send) and receives the contents of the register back (4 bytes recieve). During the write cycle the data all flows one way, first the register address, then the register data is sent. This is a simplification. Address auto-indexing and translation ram (where contguous memory addresses link to non-contiguous registers) confuse the matter. Why are you asking? -- atp "Torque wrenches are for the obedience of fools and the guidance of wise men" ------------------------------------------------------------------------------ FREE DOWNLOAD - uberSVN with Social Coding for Subversion. Subversion made easy with a complete admin console. Easy to use, easy to manage, easy to install, easy to extend. Get a Free download of the new open ALM Subversion platform now. http://p.sf.net/sfu/wandisco-dev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
