hm2_bspi_setup_chan

NAME
SYNTAX
DESCRIPTION
REALTIME CONSIDERATIONS
RETURN VALUE
SEE ALSO

NAME

hm2_bspi_setup_chan − setup a Hostmot2 bspi channel

SYNTAX

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)

DESCRIPTION

hm2_bspi_setup_chan allows a realtime component to claim and configure a BSPI channel on a previously configured hostmot2 board.

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 hm2_board-name.board-index.bspi.bspi-index. For example, the first index on the first hm2_5i23 board would be called hm2_5i23.0.bspi.0.

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.

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.

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)

mhz

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

delay

sets the chip select valid delay (in nS)

cpha and cpol

Set the clock phase and polarity (according to the device datasheet).

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.

noecho

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

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.

REALTIME CONSIDERATIONS

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

RETURN VALUE

Returns 0 on success and −1 on failure.

SEE ALSO

hm2_allocate_bspi_tram(3hm2), hm2_bspi_set_read_function(3hm2), hm2_bspi_set_write_function(3hm2), hm2_bspi_write_chan(3hm2), hm2_tram_add_bspi_frame(3hm2), See src/hal/drivers mesa_7i65.comp for an example usage.