spi module lets you talk to a device connected to your board using
a serial peripheral interface (SPI) bus. SPI uses a so-called master-slave
architecture with a single master. You will need to specify the connections
for three signals:
- SCLK : Serial Clock (output from master).
- MOSI : Master Output, Slave Input (output from master).
- MISO : Master Input, Slave Output (output from slave).
init(baudrate=1000000, bits=8, mode=0, sclk=pin13, mosi=pin15, miso=pin14)¶
Initialize SPI communication with the specified parameters on the specified
pins. Note that for correct communication, the parameters have to be the same on both communicating devices.
baudratedefines the speed of communication.
bitsdefines the size of bytes being transmitted. Currently only
bits=8is supported. However, this may change in the future.
modedetermines the combination of clock polarity and phase according to the following convention, with polarity as the high order bit and phase as the low order bit:
SPI Mode Polarity (CPOL) Phase (CPHA) 0 0 0 1 0 1 2 1 0 3 1 1
Polarity (aka CPOL) 0 means that the clock is at logic value 0 when idle and goes high (logic value 1) when active; polarity 1 means the clock is at logic value 1 when idle and goes low (logic value 0) when active. Phase (aka CPHA) 0 means that data is sampled on the leading edge of the clock, and 1 means on the trailing edge (viz. https://en.wikipedia.org/wiki/Signal_edge).
misoarguments specify the pins to use for each type of signal.
Read at most
nbytes. Returns what was read.
bufferof bytes to the bus.
outbuffer to the bus and read any response into the
inbuffer. The length of the buffers should be the same. The buffers can be the same object.