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Provide reset pin support for I2C #8

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Merged
merged 2 commits into from
Jan 5, 2018
Merged

Provide reset pin support for I2C #8

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82fec9f
Provide reset pin support for I2C
dhalbert Jan 5, 2018
374264b
pylint fixes
dhalbert Jan 5, 2018
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49 changes: 24 additions & 25 deletions adafruit_ssd1306.py
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Original file line number Diff line number Diff line change
Expand Up @@ -33,11 +33,16 @@

class _SSD1306:
"""Base class for SSD1306 display driver"""
def __init__(self, framebuffer, width, height, external_vcc):
#pylint: disable-msg=too-many-arguments
def __init__(self, framebuffer, width, height, external_vcc, reset):
self.framebuf = framebuffer
self.width = width
self.height = height
self.external_vcc = external_vcc
# reset may be None if not needed
self.reset_pin = reset
if self.reset_pin:
self.reset_pin.switch_to_output(value=0)
self.pages = self.height // 8
# Note the subclass must initialize self.framebuf to a framebuffer.
# This is necessary because the underlying data buffer is different
Expand Down Expand Up @@ -74,7 +79,7 @@ def init_display(self):
self.show()

def poweroff(self):
"""Turn the device Power off"""
"""Turn off the display (nothing visible)"""
self.write_cmd(SET_DISP | 0x00)

def contrast(self, contrast):
Expand All @@ -83,7 +88,7 @@ def contrast(self, contrast):
self.write_cmd(contrast)

def invert(self, invert):
"""Invert the pixels on the display"""
"""Invert all pixels on the display"""
self.write_cmd(SET_NORM_INV | (invert & 1))

def write_framebuf(self):
Expand All @@ -95,8 +100,15 @@ def write_cmd(self, cmd):
raise NotImplementedError

def poweron(self):
"""Derived class must implement this"""
raise NotImplementedError
"Reset device and turn on the display."
if self.reset_pin:
self.reset_pin.value = 1
time.sleep(0.001)
self.reset_pin.value = 0
time.sleep(0.010)
self.reset_pin.value = 1
time.sleep(0.010)
self.write_cmd(SET_DISP | 0x01)

def show(self):
"""Update the display"""
Expand All @@ -115,7 +127,7 @@ def show(self):
self.write_framebuf()

def fill(self, value):
"""Fill the display on or off"""
"""Fill the display with all ones or zeros."""
self.framebuf.fill(value)

def pixel(self, xpos, ypos, value):
Expand All @@ -139,9 +151,10 @@ class SSD1306_I2C(_SSD1306):
:param i2c: the I2C peripheral to use,
:param addr: the 8-bit bus address of the device,
:param external_vcc: whether external high-voltage source is connected.
:param reset: if needed, DigitalInOut designating reset pin
"""

def __init__(self, width, height, i2c, *, addr=0x3c, external_vcc=False):
def __init__(self, width, height, i2c, *, addr=0x3c, external_vcc=False, reset=None):
self.i2c_device = i2c_device.I2CDevice(i2c, addr)
self.addr = addr
self.temp = bytearray(2)
Expand All @@ -153,7 +166,7 @@ def __init__(self, width, height, i2c, *, addr=0x3c, external_vcc=False):
self.buffer = bytearray(((height // 8) * width) + 1)
self.buffer[0] = 0x40 # Set first byte of data buffer to Co=0, D/C=1
framebuffer = framebuf.FrameBuffer1(memoryview(self.buffer)[1:], width, height)
super().__init__(framebuffer, width, height, external_vcc)
super().__init__(framebuffer, width, height, external_vcc, reset)

def write_cmd(self, cmd):
"""Send a command to the SPI device"""
Expand All @@ -168,10 +181,6 @@ def write_framebuf(self):
with self.i2c_device:
self.i2c_device.write(self.buffer)

def poweron(self):
"""Turn power on the device"""
self.write_cmd(SET_DISP | 0x01)

#pylint: disable-msg=too-many-arguments
class SSD1306_SPI(_SSD1306):
"""
Expand All @@ -181,21 +190,19 @@ class SSD1306_SPI(_SSD1306):
:param height: the height of the physical screen in pixels,
:param spi: the SPI peripheral to use,
:param dc: the data/command pin to use (often labeled "D/C"),
:param res: the reset pin to use,
:param reset: the reset pin to use,
:param cs: the chip-select pin to use (sometimes labeled "SS").
"""
def __init__(self, width, height, spi, dc, res, cs, *,
def __init__(self, width, height, spi, dc, reset, cs, *,
external_vcc=False, baudrate=8000000, polarity=0, phase=0):
self.rate = 10 * 1024 * 1024
dc.switch_to_output(value=0)
res.switch_to_output(value=0)
self.spi_device = spi_device.SPIDevice(spi, cs, baudrate=baudrate,
polarity=polarity, phase=phase)
self.dc_pin = dc
self.reset_pin = res
self.buffer = bytearray((height // 8) * width)
framebuffer = framebuf.FrameBuffer1(self.buffer, width, height)
super().__init__(framebuffer, width, height, external_vcc)
super().__init__(framebuffer, width, height, external_vcc, reset)

def write_cmd(self, cmd):
"""Send a command to the SPI device"""
Expand All @@ -208,11 +215,3 @@ def write_framebuf(self):
self.dc_pin.value = 1
with self.spi_device as spi:
spi.write(self.buffer)

def poweron(self):
"""Turn power off on the device"""
self.reset_pin.value = 1
time.sleep(0.001)
self.reset_pin.value = 0
time.sleep(0.010)
self.reset_pin.value = 1