class spibus():
"""Class provided in Acme Systems' playground examples spisend.py.
"""
fd=None
write_buffer = create_string_buffer(8192)
read_buffer = create_string_buffer(8192)
ioctl_arg = spi_ioc_transfer(tx_buf=addressof(write_buffer),
rx_buf=addressof(read_buffer),
len=1,
delay_usecs=0,
speed_hz=5000000,
bits_per_word=8,
cs_change = 0)
def __init__(self, device, cs):
self._cs = Pin(cs, 'HIGH')
self.fd = posix.open(device, posix.O_RDWR)
ioctl(self.fd, SPI_IOC_RD_MODE, " ")
ioctl(self.fd, SPI_IOC_WR_MODE, struct.pack('I',0))
def send(self, len):
self._cs.low()
self.ioctl_arg.len=len
ioctl(self.fd, SPI_IOC_MESSAGE(1), addressof(self.ioctl_arg))
self._cs.high()
def write(self, s):
i = 0
for c in s:
if c.__class__ is not str:
c = chr(c)
self.write_buffer[i] = c
i += 1
self.send(len(s))
class SSD1306():
def __init__(self, rst, dc, cs, spi="/dev/spidev32766.0"):
self._log = logging.getLogger('Adafruit_SSD1306.SSD1306Base')
self.width = 128
self.height = 64
self._pages = self.height/8
self._buffer = [0]*(self.width*self._pages)
# Setup reset, DC and CS pins
self._rst = Pin(rst, 'HIGH')
self._dc = Pin(dc, 'HIGH')
# Handle hardware SPI
self._log.debug('Using hardware SPI')
self._spi = spibus(spi, cs)
def _initialize(self):
# 128x64 pixel specific initialization.
self.command(SSD1306_DISPLAYOFF) # 0xAE
self.command(SSD1306_SETDISPLAYCLOCKDIV) # 0xD5
self.command(0x80) # the suggested ratio 0x80
self.command(SSD1306_SETMULTIPLEX) # 0xA8
self.command(0x3F)
self.command(SSD1306_SETDISPLAYOFFSET) # 0xD3
self.command(0x0) # no offset
self.command(SSD1306_SETSTARTLINE | 0x0) # line #0
self.command(SSD1306_CHARGEPUMP) # 0x8D
if self._vccstate == SSD1306_EXTERNALVCC:
self.command(0x10)
else:
self.command(0x14)
self.command(SSD1306_MEMORYMODE) # 0x20
self.command(0x00) # 0x0 act like ks0108
self.command(SSD1306_SEGREMAP | 0x1)
self.command(SSD1306_COMSCANDEC)
self.command(SSD1306_SETCOMPINS) # 0xDA
self.command(0x12)
self.command(SSD1306_SETCONTRAST) # 0x81
if self._vccstate == SSD1306_EXTERNALVCC:
self.command(0x9F)
else:
self.command(0xCF)
self.command(SSD1306_SETPRECHARGE) # 0xd9
if self._vccstate == SSD1306_EXTERNALVCC:
self.command(0x22)
else:
self.command(0xF1)
self.command(SSD1306_SETVCOMDETECT) # 0xDB
self.command(0x40)
self.command(SSD1306_DISPLAYALLON_RESUME) # 0xA4
self.command(SSD1306_NORMALDISPLAY) # 0xA6
def command(self, c):
"""Send command byte to display. D/C low = Command."""
# SPI write.
self._dc.low()
self._spi.write([c])
def data(self, c):
"""Send byte of data to display. D/C high = Data."""
self._dc.high()
self._spi.write([c])
def begin(self, vccstate=SSD1306_SWITCHCAPVCC):
"""Initialize display."""
# Save vcc state.
self._vccstate = vccstate
# Reset and initialize display.
self.reset()
self._initialize()
# Turn on the display.
self.command(SSD1306_DISPLAYON)
def reset(self):
"""Reset the display."""
# Set reset high for a millisecond.
self._rst.high()
time.sleep(0.001)
# Set reset low for 10 milliseconds.
self._rst.low()
time.sleep(0.010)
# Set reset high again.
self._rst.high()
def display(self):
"""Write display buffer to physical display."""
self.command(SSD1306_COLUMNADDR)
self.command(0) # Column start address. (0 = reset)
self.command(self.width-1) # Column end address.
self.command(SSD1306_PAGEADDR)
self.command(0) # Page start address. (0 = reset)
self.command(self._pages-1) # Page end address.
# Write buffer data.
# Set DC high for data.
self._dc.high()
# Write buffer.
self._spi.write(self._buffer)
def image(self, image):
"""Set buffer to value of Python Imaging Library image. The image should
be in 1 bit mode and a size equal to the display size.
"""
if image.mode != '1':
raise ValueError('Image must be in mode 1.')
imwidth, imheight = image.size
if imwidth != self.width or imheight != self.height:
raise ValueError('Image must be same dimensions as display ({0}x{1}).'.format(self.width, self.height))
# Grab all the pixels from the image, faster than getpixel.
pix = image.load()
# Iterate through the memory pages
index = 0
for page in range(self._pages):
# Iterate through all x axis columns.
for x in range(self.width):
# Set the bits for the column of pixels at the current position.
bits = 0
# Don't use range here as it's a bit slow
for bit in [0, 1, 2, 3, 4, 5, 6, 7]:
bits = bits << 1
bits |= 0 if pix[(x, page*8+7-bit)] == 0 else 1
# Update buffer byte and increment to next byte.
self._buffer[index] = bits
index += 1
def clear(self):
"""Clear contents of image buffer."""
self._buffer = [0]*(self.width*self._pages)
def set_contrast(self, contrast):
"""Sets the contrast of the display. Contrast should be a value between
0 and 255."""
if contrast < 0 or contrast > 255:
raise ValueError('Contrast must be a value from 0 to 255 (inclusive).')
self.command(SSD1306_SETCONTRAST)
self.command(contrast)
def dim(self, dim):
"""Adjusts contrast to dim the display if dim is True, otherwise sets the
contrast to normal brightness if dim is False.
"""
# Assume dim display.
contrast = 0
# Adjust contrast based on VCC if not dimming.
if not dim:
if self._vccstate == SSD1306_EXTERNALVCC:
contrast = 0x9F
else:
contrast = 0xCF
