hm2_bspi_setup_chan − setup a Hostmot2 bspi channel
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int hm2_bspi_setup_chan(char *name, int chan, int cs, int bits, float mhz, int delay, int cpol, int cpha, int clear, int echo) |
hm2_bspi_setup_chan
Setup the bspi channel "chan" on the bspi instance
"name". "name" is a unique string given
to each 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.<index> For example
hm2_5i23.0.bspi.0 Channels are numbered 0 to 15. The value
on the chip-select lines is set by cs and need not match the
channel number. 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. "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"
is the clock phase and "cpol" is the clock
polarity (from the device datasheet). "clear"
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. "echo" is
sense-inverted, it should be set to 1 for devices which do
not return data (such
as DACs).
Returns 0 on success and -1 on failure.
man hm2_bspi_setup_chan, man hm2_bspi_write_chan, man hm2_tram_add_bspi_frame man hm2_allocate_bspi_tram. See src/hal/drivers mesa_7i65.comp for an example usage.