\# Author Andy Pugh
\# Issued under the terms of the GPL v2 License or any later version
.TH hm2_bspi_setup_chan "3hm2" "2011-05-31" "LinuxCNC Documentation" "Hostmot2"
.SH NAME

hm2_bspi_setup_chan \- setup a Hostmot2 bspi channel

.SH SYNTAX
.nf
.B #include <hostmot2-serial.h>
.HP
int hm2_bspi_setup_chan(char *name, int chan, int cs, int bits, float mhz,
int delay, int cpol, int cpha, int noclear, int noecho)

.SH DESCRIPTION
\fBhm2_bspi_setup_chan\fR allows a realtime component to claim and configure
a BSPI channel on a previously configured hostmot2 board.

.IP name
A unique string given to the BSPI channel during hostmot2 setup.
The names of the available
channels are printed to standard output during the driver loading process and 
take the form \fBhm2_\fIboard-name\fB.\fIboard-index\fB.bspi.\fIbspi-index\fR.
For example, the first index on the first hm2_5i23 board would be called hm2_5i23.0.bspi.0.

.IP chan
Channels are numbered 0 to 15.  The value on the chip-select lines is set by cs
and need not match the channel number.

.IP cs
The chip select line(s) to assert when accessing this channel.
BSPI supports 4 chip select lines, so the valid range for cs is 
0-15.

.IP bits
sets the bit-length of the SPI packet. The maximum supported length
is 64 bits but this will span two read FIFO entries and will need special 
handling. (values 32 and below require no special handling)

.IP mhz
sets the chip communication rate. The maximum value for this is 
half the FPGA base frequency, so for example with a 48 MHz 5i23 the max SPI 
frequency is 24 MHz. Values in excess of the max supported will be silently 
rounded down.

.IP delay
sets the chip select valid delay (in nS)

.IP cpha\ and\ cpol
Set the clock phase and polarity (according to the device datasheet). 

.IP noclear
controls whether the frame clear bit is set after the 32 bit buffer 
transfer. This parameter should be set to 1 when the frame length is greater 
than 32 bits and the next data in the FIFO contains the other bits.

.IP noecho
Set to 1 for devices which do not return data (such as DACs).

.IP samplelate
Set to 1 to sample the received SPI data 1/2 SPI clock later than normal.
This is useful when high clock rates or isolation cause significant delays from clock to received data.

.SH REALTIME CONSIDERATIONS
Call only from within user or init/cleanup code, not from relatime tasks.

.SH RETURN VALUE
Returns 0 on success and \-1 on failure.

.SH SEE ALSO
\fBhm2_allocate_bspi_tram(3hm2)\fR,
\fBhm2_bspi_set_read_function(3hm2)\fR,
\fBhm2_bspi_set_write_function(3hm2)\fR,
\fBhm2_bspi_write_chan(3hm2)\fR,
\fBhm2_tram_add_bspi_frame(3hm2)\fR,
See src/hal/drivers mesa_7i65.comp for an example usage.
