src/adafruit_blinka/microcontroller/ftdi_mpsse/mpsse/i2c.py

   1 """I2C Class for FTDI MPSSE"""
   2 from adafruit_blinka.microcontroller.ftdi_mpsse.mpsse.pin import Pin
   3
   4 class I2C:
   5     """Custom I2C Class for FTDI MPSSE"""
   6
   7     MASTER = 0
   8     SLAVE = 1
   9     _mode = None
  10
  11     # pylint: disable=unused-argument
  12     def __init__(self, id=None, mode=MASTER, baudrate=None, frequency=400000):
  13         if mode != self.MASTER:
  14             raise NotImplementedError("Only I2C Master supported!")
  15         _mode = self.MASTER
  16
  17         # change GPIO controller to I2C
  18         # pylint: disable=import-outside-toplevel
  19         from pyftdi.i2c import I2cController
  20
  21         # pylint: enable=import-outside-toplevel
  22
  23         self._i2c = I2cController()
  24         if id is None:
  25             self._i2c.configure("ftdi://ftdi:ft232h/1", frequency=frequency)
  26         else:
  27             self._i2c.configure("ftdi://ftdi:ft2232h/{}".format(id+1), frequency=frequency)
  28         Pin.mpsse_gpio = self._i2c.get_gpio()
  29
  30     def scan(self):
  31         """Perform an I2C Device Scan"""
  32         return [addr for addr in range(0x79) if self._i2c.poll(addr)]
  33
  34     def writeto(self, address, buffer, *, start=0, end=None, stop=True):
  35         """Write data from the buffer to an address"""
  36         end = end if end else len(buffer)
  37         port = self._i2c.get_port(address)
  38         port.write(buffer[start:end], relax=stop)
  39
  40     def readfrom_into(self, address, buffer, *, start=0, end=None, stop=True):
  41         """Read data from an address and into the buffer"""
  42         end = end if end else len(buffer)
  43         port = self._i2c.get_port(address)
  44         result = port.read(len(buffer[start:end]), relax=stop)
  45         for i, b in enumerate(result):
  46             buffer[start + i] = b
  47
  48     # pylint: disable=unused-argument
  49     def writeto_then_readfrom(
  50         self,
  51         address,
  52         buffer_out,
  53         buffer_in,
  54         *,
  55         out_start=0,
  56         out_end=None,
  57         in_start=0,
  58         in_end=None,
  59         stop=False
  60     ):
  61         """Write data from buffer_out to an address and then
  62         read data from an address and into buffer_in
  63         """
  64         out_end = out_end if out_end else len(buffer_out)
  65         in_end = in_end if in_end else len(buffer_in)
  66         port = self._i2c.get_port(address)
  67         result = port.exchange(
  68             buffer_out[out_start:out_end], in_end - in_start, relax=True
  69         )
  70         for i, b in enumerate(result):
  71             buffer_in[in_start + i] = b
  72
  73     # pylint: enable=unused-argument