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pyb.SPI.rst
Damien George authored
By virtue of its name, the pyb module would only be available on a pyboard and so does not need to have conditional "only" directives throughout its documentation. These conditionals were added mostly in cfcf47c0 in the initial development of the cc3200 port, which had the pyb module before it switched to the machine module. And wipy only conditionals were removed from the pyb module documentation in 45426430, so there's no need to retain any more conditionals.
pyb.SPI.rst 4.47 KiB
class SPI -- a master-driven serial protocol
SPI is a serial protocol that is driven by a master. At the physical level there are 3 lines: SCK, MOSI, MISO.
See usage model of I2C; SPI is very similar. Main difference is parameters to init the SPI bus:
from pyb import SPI
spi = SPI(1, SPI.MASTER, baudrate=600000, polarity=1, phase=0, crc=0x7)Only required parameter is mode, SPI.MASTER or SPI.SLAVE. Polarity can be 0 or 1, and is the level the idle clock line sits at. Phase can be 0 or 1 to sample data on the first or second clock edge respectively. Crc can be None for no CRC, or a polynomial specifier.
Additional methods for SPI:
data = spi.send_recv(b'1234') # send 4 bytes and receive 4 bytes
buf = bytearray(4)
spi.send_recv(b'1234', buf) # send 4 bytes and receive 4 into buf
spi.send_recv(buf, buf) # send/recv 4 bytes from/to buf