SPI OPEN speed, mode, bits
Communications via an SPI channel. See Appendix D for the details.
nbr is the number of data items to send or receive
SPI READ nbr, array()
array must be a single dimension float or integer array and nbr elements will be received.
SPI WRITE nbr, data1, data2, data3, … etc
data1, data2, ... can be float or integer and in the case of WRITE can be a constant or expression.
SPI WRITE nbr, string$
If string$ is used nbr characters will be sent.
SPI WRITE nbr, array()
array must be a single dimension float or integer array and nbr elements will be sent.
SPI CLOSE
Close SPI connection
SPI2 ...
The same set of commands as for SPI (above) but applying to the second SPI channel.