The data sent over a SPI connection has a number of _bits_ to represent each value. Also, position of the clock signal (SCK), ``high`` or ``low``, and the exact time when a data value is read is determined by the SPI _mode_. Both the bits and mode values together are called the _SPI format_.
### ~ hint
**Simulator**: This function needs real hardware to work with. It's not supported in the simulator.
### ~
The default number of bits is `8` and the default mode value is `3`.
## Parameters
* **bits**: the [number](types/number) of bits for each data value sent and received on the SPI connection. This value must be ``8`` since only 8 bits is currently supported for SPI data values.
* **mode**: a [number](/types/number) that is the mode value for the SPI clock (**SCK**) signalling. The different modes are:
>* `0`: the data line is active when **SCK** goes to ``high`` and the data values are read when **SCK** goes to ``high``
>* `1`: the data line is active when **SCK** goes to ``high`` and the data values are read when **SCK** goes to ``low``
>* `2`: the data line is active when **SCK** goes to ``low`` and the data values are read when **SCK** goes to ``high``
>* `3`: the data line is active when **SCK** goes to ``low`` and the data values are read when **SCK** goes to ``low``
