Using the keyword argument cs=nnn in the constructor. The cs1
pin has to be defined in mpconfigboard.h.
Note: Only a few boards have the CS1 pin exposed to the connectors.
The Pin config setting by IOMUXC_SetPinConfig() is supplied by a
bit pattern. That pattern is specific for a MCU family. In preparation
for supporting the MIMXRT117x family, the constant bit pattern is
replaced by a function call, such that the bit pattern is created
at a single place. The code for this functions was taken from
machine_pin.c.
Note: A working port for the MIMXRT1176 exists already.
This library file has a bug, in that TransferBlocking returns before the
transfer has finished. That is a problem if a write follows immediately
a read.
This class supports SPI bus controller mode, with blocking transfers.
SPI device numbers start at 0, to comply with the pinout of the Teensy
boards. With the configured clock frequency the fastest baud rate is
33MHz. For messages longer 16 bytes DMA is used. The class uses the
existing framework with extmod/machine_spi.c.
Extended driver options:
- drive=n with n being between 1 and 6 or PIN.POWER_1 to PIN.POWER_6.
Since the pins used by the SPI are fixed, no Pin settings can be made.
Thus the drive option is added allowing to control ringing and crosstalk
on the connection.
- gap_ns=nnnnn is the time between sent data items in a frame given in ns.
Default is 2 clock cycles.
