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Merged
merged 2 commits into from
Oct 14, 2019
Merged

Convert to BusDevice #9

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7c09c0f
convert to BusDevice
caternuson Oct 14, 2019
de585fc
lints
caternuson Oct 14, 2019
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45 changes: 17 additions & 28 deletions adafruit_mcp4725.py
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@
CircuitPython module for the MCP4725 digital to analog converter. See
examples/mcp4725_simpletest.py for a demo of the usage.

* Author(s): Tony DiCola
* Author(s): Tony DiCola, Carter Nelson

Implementation Notes
--------------------
Expand All @@ -42,6 +42,7 @@
https://github.com/adafruit/circuitpython/releases
"""
from micropython import const
from adafruit_bus_device import i2c_device

__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_MCP4725.git"
Expand Down Expand Up @@ -71,43 +72,31 @@ def __init__(self, i2c, *, address=_MCP4725_DEFAULT_ADDRESS):
# This device doesn't use registers and instead just accepts a single
# command string over I2C. As a result we don't use bus device or
# other abstractions and just talk raw I2C protocol.
self._i2c = i2c
self._i2c = i2c_device.I2CDevice(i2c, address)
self._address = address

def _write_fast_mode(self, val):
# Perform a 'fast mode' write to update the DAC value.
# Will not enter power down, update EEPROM, or any other state beyond
# the 12-bit DAC value.
assert 0 <= val <= 4095
try:
# Make sure bus is locked before write.
while not self._i2c.try_lock():
pass
# Build bytes to send to device with updated value.
val &= 0xFFF
self._BUFFER[0] = _MCP4725_WRITE_FAST_MODE | (val >> 8)
self._BUFFER[1] = val & 0xFF
self._i2c.writeto(self._address, self._BUFFER, end=2)
finally:
# Ensure bus is always unlocked.
self._i2c.unlock()
# Build bytes to send to device with updated value.
val &= 0xFFF
self._BUFFER[0] = _MCP4725_WRITE_FAST_MODE | (val >> 8)
self._BUFFER[1] = val & 0xFF
with self._i2c as i2c:
i2c.write(self._BUFFER, end=2)

def _read(self):
# Perform a read of the DAC value. Returns the 12-bit value.
try:
# Make sure bus is locked before write.
while not self._i2c.try_lock():
pass
# Read 3 bytes from device.
self._i2c.readfrom_into(self._address, self._BUFFER)
# Grab the DAC value from last two bytes.
dac_high = self._BUFFER[1]
dac_low = self._BUFFER[2] >> 4
# Reconstruct 12-bit value and return it.
return ((dac_high << 4) | dac_low) & 0xFFF
finally:
# Ensure bus is always unlocked.
self._i2c.unlock()
# Read 3 bytes from device.
with self._i2c as i2c:
i2c.readinto(self._BUFFER)
# Grab the DAC value from last two bytes.
dac_high = self._BUFFER[1]
dac_low = self._BUFFER[2] >> 4
# Reconstruct 12-bit value and return it.
return ((dac_high << 4) | dac_low) & 0xFFF

@property
def value(self):
Expand Down