src/adafruit_blinka/microcontroller/ft232h/i2c.py

   1 """I2C Class for FT232H"""
   2 from adafruit_blinka.microcontroller.ft232h.pin import Pin
   3
   4
   5 class I2C:
   6     """Custom I2C Class for FT232H"""
   7
   8     def __init__(self, *, frequency=400000):
   9         # change GPIO controller to I2C
  10         # pylint: disable=import-outside-toplevel
  11         from pyftdi.i2c import I2cController
  12
  13         # pylint: enable=import-outside-toplevel
  14
  15         self._i2c = I2cController()
  16         self._i2c.configure("ftdi://ftdi:ft232h/1", frequency=frequency)
  17         Pin.ft232h_gpio = self._i2c.get_gpio()
  18
  19     def scan(self):
  20         """Perform an I2C Device Scan"""
  21         return [addr for addr in range(0x79) if self._i2c.poll(addr)]
  22
  23     def writeto(self, address, buffer, *, start=0, end=None, stop=True):
  24         """Write data from the buffer to an address"""
  25         end = end if end else len(buffer)
  26         port = self._i2c.get_port(address)
  27         port.write(buffer[start:end], relax=stop)
  28
  29     def readfrom_into(self, address, buffer, *, start=0, end=None, stop=True):
  30         """Read data from an address and into the buffer"""
  31         end = end if end else len(buffer)
  32         port = self._i2c.get_port(address)
  33         result = port.read(len(buffer[start:end]), relax=stop)
  34         for i, b in enumerate(result):
  35             buffer[start + i] = b
  36
  37     # pylint: disable=unused-argument
  38     def writeto_then_readfrom(
  39         self,
  40         address,
  41         buffer_out,
  42         buffer_in,
  43         *,
  44         out_start=0,
  45         out_end=None,
  46         in_start=0,
  47         in_end=None,
  48         stop=False
  49     ):
  50         """Write data from buffer_out to an address and then
  51         read data from an address and into buffer_in
  52         """
  53         out_end = out_end if out_end else len(buffer_out)
  54         in_end = in_end if in_end else len(buffer_in)
  55         port = self._i2c.get_port(address)
  56         result = port.exchange(
  57             buffer_out[out_start:out_end], in_end - in_start, relax=True
  58         )
  59         for i, b in enumerate(result):
  60             buffer_in[in_start + i] = b
  61
  62     # pylint: enable=unused-argument