Instrument-control Toolkit - spi_read
- Loadable Function: 
[data, count] =spi_read(spi, n) -  
Read from spi slave device.
Inputs
spi - instance of octave_spi class.
n - number of bytes to attempt to read of type Integer.Outputs
The spi_read() shall return number of bytes successfully read in count as Integer and the bytes themselves in data as uint8 array.