101 lines
4.3 KiB
Python
101 lines
4.3 KiB
Python
# Copyright (c) 2014 Adafruit Industries
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# Author: Tony DiCola
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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from __future__ import division
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# Constants
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DEFAULT_ADDRESS = 0x70
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HT16K33_BLINK_CMD = 0x80
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HT16K33_BLINK_DISPLAYON = 0x01
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HT16K33_BLINK_OFF = 0x00
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HT16K33_BLINK_2HZ = 0x02
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HT16K33_BLINK_1HZ = 0x04
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HT16K33_BLINK_HALFHZ = 0x06
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HT16K33_SYSTEM_SETUP = 0x20
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HT16K33_OSCILLATOR = 0x01
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HT16K33_CMD_BRIGHTNESS = 0xE0
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class HT16K33(object):
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"""Driver for interfacing with a Holtek HT16K33 16x8 LED driver."""
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def __init__(self, address=DEFAULT_ADDRESS, i2c=None, **kwargs):
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"""Create an HT16K33 driver for device on the specified I2C address
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(defaults to 0x70) and I2C bus (defaults to platform specific bus).
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"""
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if i2c is None:
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import Adafruit_GPIO.I2C as I2C
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i2c = I2C
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self._device = i2c.get_i2c_device(address, **kwargs)
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self.buffer = bytearray([0]*16)
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def begin(self):
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"""Initialize driver with LEDs enabled and all turned off."""
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# Turn on the oscillator.
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self._device.writeList(HT16K33_SYSTEM_SETUP | HT16K33_OSCILLATOR, [])
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# Turn display on with no blinking.
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self.set_blink(HT16K33_BLINK_OFF)
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# Set display to full brightness.
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self.set_brightness(15)
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def set_blink(self, frequency):
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"""Blink display at specified frequency. Note that frequency must be a
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value allowed by the HT16K33, specifically one of: HT16K33_BLINK_OFF,
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HT16K33_BLINK_2HZ, HT16K33_BLINK_1HZ, or HT16K33_BLINK_HALFHZ.
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"""
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if frequency not in [HT16K33_BLINK_OFF, HT16K33_BLINK_2HZ,
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HT16K33_BLINK_1HZ, HT16K33_BLINK_HALFHZ]:
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raise ValueError('Frequency must be one of HT16K33_BLINK_OFF, HT16K33_BLINK_2HZ, HT16K33_BLINK_1HZ, or HT16K33_BLINK_HALFHZ.')
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self._device.writeList(HT16K33_BLINK_CMD | HT16K33_BLINK_DISPLAYON | frequency, [])
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def set_brightness(self, brightness):
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"""Set brightness of entire display to specified value (16 levels, from
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0 to 15).
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"""
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if brightness < 0 or brightness > 15:
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raise ValueError('Brightness must be a value of 0 to 15.')
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self._device.writeList(HT16K33_CMD_BRIGHTNESS | brightness, [])
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def set_led(self, led, value):
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"""Sets specified LED (value of 0 to 127) to the specified value, 0/False
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for off and 1 (or any True/non-zero value) for on.
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"""
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if led < 0 or led > 127:
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raise ValueError('LED must be value of 0 to 127.')
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# Calculate position in byte buffer and bit offset of desired LED.
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pos = led // 8
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offset = led % 8
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if not value:
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# Turn off the specified LED (set bit to zero).
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self.buffer[pos] &= ~(1 << offset)
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else:
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# Turn on the speciried LED (set bit to one).
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self.buffer[pos] |= (1 << offset)
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def write_display(self):
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"""Write display buffer to display hardware."""
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for i, value in enumerate(self.buffer):
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self._device.write8(i, value)
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def clear(self):
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"""Clear contents of display buffer."""
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for i, value in enumerate(self.buffer):
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self.buffer[i] = 0
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