python/bitbangio/__init__.py

   1 from machine import Pin, I2C as _I2C
   2
   3 class I2C:
   4     def __init__(self, scl, sda, frequency=400000):
   5         self.init(scl, sda, frequency)
   6
   7     def init(self, scl, sda, frequency):
   8         self.deinit()
   9         id = -1 # force bitbanging implementation - in future introspect platform if SDA/SCL matches hardware I2C
  10         self._i2c = _I2C(id, Pin(scl.id), Pin(sda.id), frequency)
  11
  12     def deinit(self):
  13         try:
  14             del self._i2c
  15         except AttributeError:
  16             pass
  17
  18     def __enter__(self):
  19         return self
  20
  21     def __exit__(self, exc_type, exc_value, traceback):
  22         self.deinit()
  23
  24     def scan(self):
  25         return self._i2c.scan()
  26
  27     def try_lock(self):
  28         if self._locked:
  29             return False
  30         else:
  31             self._locked=True
  32             return True
  33
  34     def unlock(self):
  35         if self._locked:
  36             self._locked = False
  37         else:
  38             raise ValueError("Not locked")
  39
  40     def readfrom_into(self, address, buffer, start=0, end=None):
  41         if start is not 0 or end is not None:
  42             if end is None:
  43                 end = len(buffer)
  44             buffer = memoryview(buffer)[start:end]
  45         return self._i2c.readfrom_into(address, buffer, stop=False)
  46
  47     def writeto(self, address, buffer, start=0, end=None, stop=True):
  48         if start is not 0 or end is not None:
  49             if end is None:
  50                 end = len(buffer)
  51             buffer = memoryview(buffer)[start:end]
  52         return self._i2c.writeto(address, buffer, stop)