src/adafruit_blinka/microcontroller/ft232h/i2c.py

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