NAME

       hm2_7i90  -  LinuxCNC  HAL  driver  for  the  Mesa  Electronics  7i90 EPP Anything IO board with HostMot2
       firmware.

SYNOPSIS

       loadrt hm2_7i90 [ioaddr=N[,N...]] [ioaddr_hi=N[,N...]] [epp_wide=N[,N...]] [debug_epp=N[,N...]]

           ioaddr [default: 0 (parport0)]
                  The base address of the parallel port.

                  The number of ioaddr indexes/addresses given is used by  the  driver  to  determine  how  many
                  boards  to  search  for.  Previously the number of config strings was used, but a blank config
                  string is perfectly acceptable for 7i90.

           ioaddr_hi [default: 0]
                  The secondary address of the parallel port, used to set EPP mode.  0 means  to  use  ioaddr  +
                  0x400.

           epp_wide [default: 1]
                  Set  to  zero  to  disable  the  "wide  EPP  mode".   "Wide"  mode allows a 16- and 32-bit EPP
                  transfers, which can reduce the time spent in the read and write functions.  However, this may
                  not work on all EPP parallel ports.

           config [default: ""]
                  HostMot2 config strings, described in the hostmot2(9) manpage.

           debug_epp [default: 0]
                  Developer/debug use only!  Enable debug logging of most EPP transfers.

DESCRIPTION

       hm2_7i90 is a device driver that interfaces the Mesa  7i90  board  with  the  HostMot2  firmware  to  the
       LinuxCNC HAL.

       The  7i90  firmware  is  stored on the 7i90 itself, it is not programmed by the driver at load time.  The
       7i90 firmware can be changed using the mesaflash program.

       The driver talks with the 7i90 over the parallel port, via EPP.

Communicating with the board

       The 7i90 communicates with the LinuxCNC computer over EPP, the Enhanced  Parallel  Port.   This  provides
       about 1 MBps of throughput, and the communication latency is very predictable and reasonably low.

       The parallel port must support EPP 1.7 or EPP 1.9.  EPP 1.9 is preferred, but EPP 1.7 will work too.  The
       EPP mode of the parallel port is sometimes a setting in the BIOS.

       Note  that  the  popular "NetMOS" aka "MosChip 9805" PCI parport cards do not work.  They do not meet the
       EPP spec, and cannot be reliably used with the 7i90.  You have to find another card, sorry.

       EPP is very reliable under normal circumstances, but bad cabling or excessively  long  cabling  runs  may
       cause  communication  timeouts.   The  driver  exports  a parameter named hm2_7i90.<BoardNum>.io_error to
       inform HAL of this condition.  When the driver detects an EPP timeout, it sets io_error to True and stops
       communicating with the 7i90 board.  Setting io_error back to False  makes  the  driver  start  trying  to
       communicate with the 7i90 again.

       Access to the EPP bus is not threadsafe: only one realtime thread may access the EPP bus.

SEE ALSO

       hostmot2(9)

LICENSE

       GPL

LinuxCNC Documentation                             2013-10-27                                        HM2_7I90(9)