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i2c.py
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import time
class I2C:
def __init__(self, scl, sda):
self.scl = scl
self.sda = sda
def _delay(self):
time.sleep_us(100)
def init(self):
self.scl.on()
self.sda.on()
self._delay()
def start(self):
self.scl.on()
self.sda.on()
self._delay()
self.sda.off()
self._delay()
self.scl.off()
self._delay()
def stop(self):
self.sda.off()
self._delay()
self.scl.on()
self._delay()
self.sda.on()
self._delay()
def write_bit(self, b):
if (b > 0):
self.sda.on()
else:
self.sda.off()
self._delay()
self.scl.on()
self._delay()
self.scl.off()
def read_bit(self):
self.sda.on()
self._delay()
self.scl.on()
self._delay()
if self.sda.value():
b = 1
else:
b = 0
self.scl.off()
return b
def write_byte(self, byte, start=True, stop=True):
if start:
self.start()
for x in range(8):
self.write_bit(byte & 0x80)
byte = byte << 1
ack = self.read_bit()
if stop:
self.stop()
return ack
def read_byte(self, ack=True, stop=True):
byte = 0
for x in range(8):
byte = byte << 1
byte |= self.read_bit()
if ack:
self.write_bit(0)
else:
self.write_bit(1)
if stop:
self.stop()
return byte
def send(self, addr, data):
if self.write_byte(addr << 1, True, False):
if self.write_byte(data, False, True):
return True
self.stop()
return False
def receive(self, addr):
if self.write_byte(addr << 1 | 0x01, True, False):
return self.read_byte(False, True)
return False