class SPI:
MSB = 0
- baudrate = 100000
- mode = 0
- bits = 8
-
def __init__(self):
- # change GPIO controller to SPI
from pyftdi.spi import SpiController
self._spi = SpiController(cs_count=1)
self._spi.configure('ftdi:///1')
+ self._port = self._spi.get_port(0)
+ self._port.set_frequency(100000)
+ self._port._cpol = 0
+ self._port._cpha = 0
+ # Change GPIO controller to SPI
Pin.ft232h_gpio = self._spi.get_gpio()
def init(self, baudrate=100000, polarity=0, phase=0, bits=8,
firstbit=MSB, sck=None, mosi=None, miso=None):
- self.cs = 0
- self.freq = baudrate
- if polarity == 0 and phase == 0:
- self.mode = 0
- elif polarity == 0 and phase == 1:
- self.mode = 1
- elif polarity == 1 and phase == 0:
- raise ValueError("SPI mode 2 is not supported.")
- elif polarity == 1 and phase == 1:
- self.mode = 3
- else:
- raise ValueError("Unknown SPI mode.")
+ self._port.set_frequency(baudrate)
+ # FTDI device can only support mode 0 and mode 2
+ # due to the limitation of MPSSE engine.
+ # This means CPHA must = 0
+ self._port._cpol = polarity
+ if phase != 0:
+ raise ValueError("Only SPI phase 0 is supported by FT232H.")
+ self._port._cpha = phase
+
+ @property
+ def frequency(self):
+ return self._port.frequency
def write(self, buf, start=0, end=None):
end = end if end else len(buf)
- port = self._spi.get_port(self.cs, self.freq, self.mode)
chunks, rest = divmod(end - start, self._spi.PAYLOAD_MAX_LENGTH)
for i in range(chunks):
chunk_start = start + i * self._spi.PAYLOAD_MAX_LENGTH
chunk_end = chunk_start + self._spi.PAYLOAD_MAX_LENGTH
- port.write(buf[chunk_start:chunk_end])
+ self._port.write(buf[chunk_start:chunk_end])
if rest:
- port.write(buf[-1*rest:])
+ self._port.write(buf[-1*rest:])
def readinto(self, buf, start=0, end=None, write_value=0):
end = end if end else len(buf)
- port = self._spi.get_port(self.cs, self.freq, self.mode)
- result = port.read(end-start)
+ result = self._port.read(end-start)
for i, b in enumerate(result):
buf[start+i] = b
def write_readinto(self, buffer_out, buffer_in, out_start=0, out_end=None, in_start=0, in_end=None):
out_end = out_end if out_end else len(buffer_out)
in_end = in_end if in_end else len(buffer_in)
- port = self._spi.get_port(self.cs, self.freq, self.mode)
- result = port.exchange(buffer_out[out_start:out_end],
- in_end-in_start, duplex=True)
+ result = self._port.exchange(buffer_out[out_start:out_end],
+ in_end-in_start, duplex=True)
for i, b in enumerate(result):
buffer_in[in_start+i] = b