src/adafruit_blinka/microcontroller/ft232h/i2c.py

   1 from adafruit_blinka.microcontroller.ft232h.pin import Pin
   2
   3 class I2C:
   4
   5     def __init__(self, *, frequency=400000):
   6         # change GPIO controller to I2C
   7         from pyftdi.i2c import I2cController
   8         self._i2c = I2cController()
   9         self._i2c.configure('ftdi:///1', frequency=frequency)
  10         Pin.ft232h_gpio = self._i2c.get_gpio()
  11
  12     def scan(self):
  13         return [addr for addr in range(0x79) if self._i2c.poll(addr)]
  14
  15     def writeto(self, address, buffer, *, start=0, end=None, stop=True):
  16         end = end if end else len(buffer)
  17         port = self._i2c.get_port(address)
  18         port.write(buffer[start:end], relax=stop)
  19
  20     def readfrom_into(self, address, buffer, *, start=0, end=None, stop=True):
  21         end = end if end else len(buffer)
  22         port = self._i2c.get_port(address)
  23         result = port.read(len(buffer[start:end]), relax=stop)
  24         for i, b in enumerate(result):
  25             buffer[start+i] = b
  26
  27     def writeto_then_readfrom(self, address, buffer_out, buffer_in, *,
  28                               out_start=0, out_end=None,
  29                               in_start=0, in_end=None, stop=False):
  30         out_end = out_end if out_end else len(buffer_out)
  31         in_end = in_end if in_end else len(buffer_in)
  32         port = self._i2c.get_port(address)
  33         result = port.exchange(buffer_out[out_start:out_end],
  34                                in_end-in_start,
  35                                relax=True).tobytes()
  36         for i, b in enumerate(result):
  37             buffer_in[in_start+i] = b