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