.TH HM2_7I43 "9" "2008-05-13" "EMC Documentation" "HAL Component"
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.SH NAME

hm2_7i43 \- RTAI driver for the Mesa Electronics 7i43 EPP Anything IO board with HostMot2 firmware.
.SH SYNOPSIS
.HP
.B loadrt hm2_7i43 [ioaddr=\fIN\fB] [ioaddr_hi=\fIN\fB] [epp_wide=\fIN\fB] [config=\fI"str"\fB] [debug_epp=\fIN\fB]
.RS 4
.TP
\fBioaddr\fR [default: 0x378]
The base address of the parallel port.
.TP
\fBioaddr_hi\fR [default: 0]
The secondary address of the parallel port, used to set EPP mode.
0 means to use ioaddr + 0x400.
.TP
\fBepp_wide\fR [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.
.TP
\fBconfig\fR [default: ""]
HostMot2 config string, described in the hostmot2(9) manpage.
.TP
\fBdebug_epp\fR [default: 0]
Developer/debug use only!  Enable debug logging of most EPP
transfers.
.RE
.SH DESCRIPTION

hm2_7i43 is an RTAI device driver that interfaces the Mesa 7i43 board with
the HostMot2 firmware to the EMC2 HAL.  Both the 200K and the 400K FPGAs
are supported.

The driver talks with the 7i43 over the parallel port, not over USB.  USB
can be used to power the 7i43, but not to talk to it.  USB communication
with the 7i43 will not be supported any time soon, since USB has poor
real-time qualities.

The driver assumes that the board is already configured with the HostMot2
firmware.  The board might get its configuration from its EEPROM, or
the bfload(1) program can be used to send a firmware image from the PC
to the 7i43 board.


.SH Jumper settings

To send the FPGA configuration from the PC, the board must be configured
to get its firmware from the EPP port.  To do this, jumpers W4 and W5
must both be down, ie toward the USB connector.

The board must be configured to power on whether or not the USB interface
is active.  This is done by setting jumper W7 up, ie away from the edge
of the board.


.SH Communicating with the board

The 7i43 communicates with the EMC computer over EPP, the Enhanced
Parallel Port.  This provides about 1 MBps of throughput, and the
communication latency is very predictable and reasonably low.

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_7i43.<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 7i43 board.
Setting io_error back to False makes the driver start trying to
communicate with the 7i43 again.


.SH SEE ALSO

hostmot2(9)
.br
bfload(1)


.SH LICENSE

GPL