add arduino code

2.9inch_e-paper_code/RaspberryPi/python2/epd2in9.py

@@ -0,0 +1,238 @@
+# /*****************************************************************************
+# * | File        :	  EPD_1in54.py
+# * | Author      :   Waveshare team
+# * | Function    :   Electronic paper driver
+# * | Info        :
+# *----------------
+# * |	This version:   V3.0
+# * | Date        :   2018-11-06
+# * | Info        :   python2 demo
+# * 1.Remove:
+#   digital_write(self, pin, value)
+#   digital_read(self, pin)
+#   delay_ms(self, delaytime)
+#   set_lut(self, lut)
+#   self.lut = self.lut_full_update
+# * 2.Change:
+#   display_frame -> TurnOnDisplay
+#   set_memory_area -> SetWindow
+#   set_memory_pointer -> SetCursor
+#   get_frame_buffer -> getbuffer
+#   set_frame_memory -> display
+# * 3.How to use
+#   epd = epd2in9.EPD()
+#   epd.init(epd.lut_full_update)
+#   image = Image.new('1', (epd1in54.EPD_WIDTH, epd1in54.EPD_HEIGHT), 255)
+#   ...
+#   drawing ......
+#   ...
+#   epd.display(getbuffer(image))
+# ******************************************************************************/
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documnetation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to  whom the Software is
+# furished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS OR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+
+
+import epdconfig
+from PIL import Image
+import RPi.GPIO as GPIO
+
+# Display resolution
+EPD_WIDTH       = 128
+EPD_HEIGHT      = 296
+
+# EPD2IN9 commands
+DRIVER_OUTPUT_CONTROL                       = 0x01
+BOOSTER_SOFT_START_CONTROL                  = 0x0C
+GATE_SCAN_START_POSITION                    = 0x0F
+DEEP_SLEEP_MODE                             = 0x10
+DATA_ENTRY_MODE_SETTING                     = 0x11
+SW_RESET                                    = 0x12
+TEMPERATURE_SENSOR_CONTROL                  = 0x1A
+MASTER_ACTIVATION                           = 0x20
+DISPLAY_UPDATE_CONTROL_1                    = 0x21
+DISPLAY_UPDATE_CONTROL_2                    = 0x22
+WRITE_RAM                                   = 0x24
+WRITE_VCOM_REGISTER                         = 0x2C
+WRITE_LUT_REGISTER                          = 0x32
+SET_DUMMY_LINE_PERIOD                       = 0x3A
+SET_GATE_TIME                               = 0x3B
+BORDER_WAVEFORM_CONTROL                     = 0x3C
+SET_RAM_X_ADDRESS_START_END_POSITION        = 0x44
+SET_RAM_Y_ADDRESS_START_END_POSITION        = 0x45
+SET_RAM_X_ADDRESS_COUNTER                   = 0x4E
+SET_RAM_Y_ADDRESS_COUNTER                   = 0x4F
+TERMINATE_FRAME_READ_WRITE                  = 0xFF
+
+class EPD:
+    def __init__(self):
+        self.reset_pin = epdconfig.RST_PIN
+        self.dc_pin = epdconfig.DC_PIN
+        self.busy_pin = epdconfig.BUSY_PIN
+        self.cs_pin = epdconfig.CS_PIN
+        self.width = EPD_WIDTH
+        self.height = EPD_HEIGHT
+
+    lut_full_update = [
+        0x02, 0x02, 0x01, 0x11, 0x12, 0x12, 0x22, 0x22, 
+        0x66, 0x69, 0x69, 0x59, 0x58, 0x99, 0x99, 0x88, 
+        0x00, 0x00, 0x00, 0x00, 0xF8, 0xB4, 0x13, 0x51, 
+        0x35, 0x51, 0x51, 0x19, 0x01, 0x00
+    ]
+
+    lut_partial_update  = [
+        0x10, 0x18, 0x18, 0x08, 0x18, 0x18, 0x08, 0x00, 
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+        0x00, 0x00, 0x00, 0x00, 0x13, 0x14, 0x44, 0x12, 
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+    ]
+        
+    # Hardware reset
+    def reset(self):
+        epdconfig.digital_write(self.reset_pin, GPIO.HIGH)
+        epdconfig.delay_ms(200) 
+        epdconfig.digital_write(self.reset_pin, GPIO.LOW)         # module reset
+        epdconfig.delay_ms(200)
+        epdconfig.digital_write(self.reset_pin, GPIO.HIGH)
+        epdconfig.delay_ms(200)   
+
+    def send_command(self, command):
+        epdconfig.digital_write(self.cs_pin, GPIO.LOW)
+        epdconfig.digital_write(self.dc_pin, GPIO.HIGH)
+        epdconfig.spi_writebyte([command])
+        epdconfig.digital_write(self.cs_pin, GPIO.HIGH)
+
+    def send_data(self, data):
+        epdconfig.digital_write(self.cs_pin, GPIO.LOW)
+        epdconfig.digital_write(self.dc_pin, GPIO.HIGH)
+        epdconfig.spi_writebyte([data])
+        epdconfig.digital_write(self.cs_pin, GPIO.HIGH)
+        
+    def wait_until_idle(self):
+        while(epdconfig.digital_read(self.busy_pin) == 1):      # 0: idle, 1: busy
+            epdconfig.delay_ms(100)    
+
+    def TurnOnDisplay(self):
+        self.send_command(DISPLAY_UPDATE_CONTROL_2)
+        self.send_data(0xC4)
+        self.send_command(MASTER_ACTIVATION)
+        self.send_command(TERMINATE_FRAME_READ_WRITE)
+        
+        self.wait_until_idle()
+
+    def SetWindow(self, x_start, y_start, x_end, y_end):
+        self.send_command(SET_RAM_X_ADDRESS_START_END_POSITION)
+        # x point must be the multiple of 8 or the last 3 bits will be ignored
+        self.send_data((x_start >> 3) & 0xFF)
+        self.send_data((x_end >> 3) & 0xFF)
+        self.send_command(SET_RAM_Y_ADDRESS_START_END_POSITION)
+        self.send_data(y_start & 0xFF)
+        self.send_data((y_start >> 8) & 0xFF)
+        self.send_data(y_end & 0xFF)
+        self.send_data((y_end >> 8) & 0xFF)
+
+    def SetCursor(self, x, y):
+        self.send_command(SET_RAM_X_ADDRESS_COUNTER)
+        # x point must be the multiple of 8 or the last 3 bits will be ignored
+        self.send_data((x >> 3) & 0xFF)
+        self.send_command(SET_RAM_Y_ADDRESS_COUNTER)
+        self.send_data(y & 0xFF)
+        self.send_data((y >> 8) & 0xFF)
+        self.wait_until_idle()
+        
+    def init(self, lut):
+        if (epdconfig.module_init() != 0):
+            return -1
+        # EPD hardware init start
+        self.reset()
+        
+        self.send_command(DRIVER_OUTPUT_CONTROL)
+        self.send_data((EPD_HEIGHT - 1) & 0xFF)
+        self.send_data(((EPD_HEIGHT - 1) >> 8) & 0xFF)
+        self.send_data(0x00)                     # GD = 0 SM = 0 TB = 0
+        self.send_command(BOOSTER_SOFT_START_CONTROL)
+        self.send_data(0xD7)
+        self.send_data(0xD6)
+        self.send_data(0x9D)
+        self.send_command(WRITE_VCOM_REGISTER)
+        self.send_data(0xA8)                     # VCOM 7C
+        self.send_command(SET_DUMMY_LINE_PERIOD)
+        self.send_data(0x1A)                     # 4 dummy lines per gate
+        self.send_command(SET_GATE_TIME)
+        self.send_data(0x08)                     # 2us per line
+        self.send_command(BORDER_WAVEFORM_CONTROL)
+        self.send_data(0x03)
+        self.send_command(DATA_ENTRY_MODE_SETTING)
+        self.send_data(0x03)                     # X increment Y increment
+        
+        self.send_command(WRITE_LUT_REGISTER)
+        for i in range(0, len(lut)):
+            self.send_data(lut[i])
+        # EPD hardware init end
+        return 0
+
+    def getbuffer(self, image):
+        # print "bufsiz = ",(self.width/8) * self.height
+        buf = [0xFF] * ((self.width/8) * self.height)
+        image_monocolor = image.convert('1')
+        imwidth, imheight = image_monocolor.size
+        pixels = image_monocolor.load()
+        # print "imwidth = %d, imheight = %d",imwidth,imheight
+        if(imwidth == self.width and imheight == self.height):
+            print "Vertical"
+            for y in range(imheight):
+                for x in range(imwidth):
+                    # Set the bits for the column of pixels at the current position.
+                    if pixels[x, y] == 0:
+                        buf[(x + y * self.width) / 8] &= ~(0x80 >> (x % 8))
+        elif(imwidth == self.height and imheight == self.width):
+            print "Horizontal"
+            for y in range(imheight):
+                for x in range(imwidth):
+                    newx = y
+                    newy = self.height - x - 1
+                    if pixels[x, y] == 0:
+                        buf[(newx + newy*self.width) / 8] &= ~(0x80 >> (y % 8))
+        return buf
+
+    def display(self, image):
+        if (image == None):
+            return            
+        self.SetWindow(0, 0, self.width - 1, self.height - 1)
+        for j in range(0, self.height):
+            self.SetCursor(0, j)
+            self.send_command(WRITE_RAM)
+            for i in range(0, self.width / 8):
+                self.send_data(image[i + j * (self.width / 8)])   
+        self.TurnOnDisplay()
+        
+    def Clear(self, color):
+        self.SetWindow(0, 0, self.width - 1, self.height - 1)
+        for j in range(0, self.height):
+            self.SetCursor(0, j)
+            self.send_command(WRITE_RAM)
+            for i in range(0, self.width / 8):
+                self.send_data(color)   
+        self.TurnOnDisplay()
+
+    def sleep(self):
+        self.send_command(DEEP_SLEEP_MODE)
+        self.send_data(0x01)
+
+### END OF FILE ###
+

2.9inch_e-paper_code/RaspberryPi/python2/epdconfig.py

@@ -0,0 +1,73 @@
+# /*****************************************************************************
+# * | File        :	  EPD_1in54.py
+# * | Author      :   Waveshare team
+# * | Function    :   Hardware underlying interface
+# * | Info        :
+# *----------------
+# * |	This version:   V2.0
+# * | Date        :   2018-11-01
+# * | Info        :   
+# * 1.Remove:
+#   digital_write(self, pin, value)
+#   digital_read(self, pin)
+#   delay_ms(self, delaytime)
+#   set_lut(self, lut)
+#   self.lut = self.lut_full_update
+# ******************************************************************************/
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documnetation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to  whom the Software is
+# furished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS OR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+
+
+import spidev
+import RPi.GPIO as GPIO
+import time
+
+# Pin definition
+RST_PIN         = 17
+DC_PIN          = 25
+CS_PIN          = 8
+BUSY_PIN        = 24
+
+# SPI device, bus = 0, device = 0
+SPI = spidev.SpiDev(0, 0)
+
+def digital_write(pin, value):
+    GPIO.output(pin, value)
+
+def digital_read(pin):
+    return GPIO.input(BUSY_PIN)
+
+def delay_ms(delaytime):
+    time.sleep(delaytime / 1000.0)
+
+def spi_writebyte(data):
+    SPI.writebytes(data)
+
+def module_init():
+    GPIO.setmode(GPIO.BCM)
+    GPIO.setwarnings(False)
+    GPIO.setup(RST_PIN, GPIO.OUT)
+    GPIO.setup(DC_PIN, GPIO.OUT)
+    GPIO.setup(CS_PIN, GPIO.OUT)
+    GPIO.setup(BUSY_PIN, GPIO.IN)
+    SPI.max_speed_hz = 2000000
+    SPI.mode = 0b00
+    return 0;
+
+### END OF FILE ###

2.9inch_e-paper_code/RaspberryPi/python2/main.py

@@ -0,0 +1,83 @@
+#!/usr/bin/python
+# -*- coding:utf-8 -*-
+
+import epd2in9
+import time
+from PIL import Image,ImageDraw,ImageFont
+import traceback
+
+try:
+    epd = epd2in9.EPD()
+    epd.init(epd.lut_full_update)
+    epd.Clear(0xFF)
+    
+    # Drawing on the Horizontal image
+    Himage = Image.new('1', (epd2in9.EPD_HEIGHT, epd2in9.EPD_WIDTH), 255)  # 255: clear the frame
+    # Drawing on the Vertical image
+    Limage = Image.new('1', (epd2in9.EPD_WIDTH, epd2in9.EPD_HEIGHT), 255)  # 255: clear the frame
+    
+    # Horizontal
+    print "Drawing"
+    draw = ImageDraw.Draw(Himage)
+    font24 = ImageFont.truetype('/usr/share/fonts/truetype/wqy/wqy-microhei.ttc', 24)
+    draw.text((10, 0), 'hello world', font = font24, fill = 0)
+    draw.text((10, 20), '2.9inch e-Paper', font = font24, fill = 0)
+    draw.text((150, 0), u'微雪电子', font = font24, fill = 0)    
+    draw.line((20, 50, 70, 100), fill = 0)
+    draw.line((70, 50, 20, 100), fill = 0)
+    draw.rectangle((20, 50, 70, 100), outline = 0)
+    draw.line((165, 50, 165, 100), fill = 0)
+    draw.line((140, 75, 190, 75), fill = 0)
+    draw.arc((140, 50, 190, 100), 0, 360, fill = 0)
+    draw.rectangle((80, 50, 130, 100), fill = 0)
+    draw.chord((200, 50, 250, 100), 0, 360, fill = 0)
+    epd.display(epd.getbuffer(Himage))
+    time.sleep(2)
+    
+    # Vertical
+    draw = ImageDraw.Draw(Limage)
+    font18 = ImageFont.truetype('/usr/share/fonts/truetype/wqy/wqy-microhei.ttc', 18)
+    draw.text((2, 0), 'hello world', font = font18, fill = 0)
+    draw.text((2, 20), '2.9inch epd', font = font18, fill = 0)
+    draw.text((20, 50), u'微雪电子', font = font18, fill = 0)
+    draw.line((10, 90, 60, 140), fill = 0)
+    draw.line((60, 90, 10, 140), fill = 0)
+    draw.rectangle((10, 90, 60, 140), outline = 0)
+    draw.line((95, 90, 95, 140), fill = 0)
+    draw.line((70, 115, 120, 115), fill = 0)
+    draw.arc((70, 90, 120, 140), 0, 360, fill = 0)
+    draw.rectangle((10, 150, 60, 200), fill = 0)
+    draw.chord((70, 150, 120, 200), 0, 360, fill = 0)
+    epd.display(epd.getbuffer(Limage))
+    time.sleep(2)
+    
+    print "read bmp file"
+    Himage = Image.open('2in9.bmp')
+    epd.display(epd.getbuffer(Himage))
+    time.sleep(2)
+    
+    print "read bmp file on window"
+    Himage2 = Image.new('1', (epd2in9.EPD_HEIGHT, epd2in9.EPD_WIDTH), 255)  # 255: clear the frame
+    bmp = Image.open('100x100.bmp')
+    Himage2.paste(bmp, (50,10))
+    epd.display(epd.getbuffer(Himage2))
+    time.sleep(2)
+    
+    # partial update
+    epd.init(epd.lut_partial_update)    
+    epd.Clear(0xFF)
+    time_image = Image.new('1', (epd2in9.EPD_HEIGHT, epd2in9.EPD_WIDTH), 255)
+    time_draw = ImageDraw.Draw(time_image)
+    while (True):
+        time_draw.rectangle((10, 10, 120, 50), fill = 255)
+        time_draw.text((10, 10), time.strftime('%H:%M:%S'), font = font24, fill = 0)
+        newimage = time_image.crop([10, 10, 120, 50])
+        time_image.paste(newimage, (10,10))  
+        epd.display(epd.getbuffer(time_image))
+        
+    epd.sleep()
+        
+except Exception, e:
+    print 'traceback.format_exc():\n%s' % traceback.format_exc()
+    exit()
+

2.9inch_e-paper_code/RaspberryPi/python2/readme.txt

@@ -0,0 +1,92 @@
+/******************************************************************************
+ * File Name          : readme.txt
+ * Description        : Readme file
+ * Date               : 2019-04-08
+ ******************************************************************************
+ *
+ * Copyright (c) 2017 Waveshare
+ * All rights reserved.
+ *
+ * THIS SOFTWARE IS PROVIDED BY COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
+ * AND ANY EXPRESS, IMPLIED OR STATUTORY WARRANTIES, INCLUDING, BUT NOT 
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
+ * PARTICULAR PURPOSE AND NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY
+ * RIGHTS ARE DISCLAIMED TO THE FULLEST EXTENT PERMITTED BY LAW. IN NO EVENT 
+ * SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
+ * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ ******************************************************************************
+  
+  == Development Environment ==
+  * OS: Raspbian for Raspberry Pi
+  * Libraries required: 
+        SPI library of Python
+        PIL (Python Imaging Library) library
+
+  == Raspberry Pi GPIO Pin map ==
+ +-----+-----+---------+------+---+---Pi 3---+---+------+---------+-----+-----+
+ | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
+ +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
+ |     |     |    3.3v |      |   |  1 || 2  |   |      | 5v      |     |     |
+ |   2 |   8 |   SDA.1 |   IN | 1 |  3 || 4  |   |      | 5v      |     |     |
+ |   3 |   9 |   SCL.1 |   IN | 1 |  5 || 6  |   |      | 0v      |     |     |
+ |   4 |   7 | GPIO. 7 |   IN | 1 |  7 || 8  | 1 | ALT5 | TxD     | 15  | 14  |
+ |     |     |      0v |      |   |  9 || 10 | 1 | ALT5 | RxD     | 16  | 15  |
+ |  17 |   0 | GPIO. 0 |   IN | 0 | 11 || 12 | 0 | IN   | GPIO. 1 | 1   | 18  |
+ |  27 |   2 | GPIO. 2 |   IN | 0 | 13 || 14 |   |      | 0v      |     |     |
+ |  22 |   3 | GPIO. 3 |   IN | 0 | 15 || 16 | 0 | IN   | GPIO. 4 | 4   | 23  |
+ |     |     |    3.3v |      |   | 17 || 18 | 0 | IN   | GPIO. 5 | 5   | 24  |
+ |  10 |  12 |    MOSI | ALT0 | 0 | 19 || 20 |   |      | 0v      |     |     |
+ |   9 |  13 |    MISO | ALT0 | 0 | 21 || 22 | 0 | IN   | GPIO. 6 | 6   | 25  |
+ |  11 |  14 |    SCLK | ALT0 | 0 | 23 || 24 | 1 | OUT  | CE0     | 10  | 8   |
+ |     |     |      0v |      |   | 25 || 26 | 1 | OUT  | CE1     | 11  | 7   |
+ |   0 |  30 |   SDA.0 |   IN | 1 | 27 || 28 | 1 | IN   | SCL.0   | 31  | 1   |
+ |   5 |  21 | GPIO.21 |   IN | 1 | 29 || 30 |   |      | 0v      |     |     |
+ |   6 |  22 | GPIO.22 |   IN | 1 | 31 || 32 | 0 | IN   | GPIO.26 | 26  | 12  |
+ |  13 |  23 | GPIO.23 |   IN | 0 | 33 || 34 |   |      | 0v      |     |     |
+ |  19 |  24 | GPIO.24 |  OUT | 1 | 35 || 36 | 1 | OUT  | GPIO.27 | 27  | 16  |
+ |  26 |  25 | GPIO.25 |   IN | 0 | 37 || 38 | 0 | IN   | GPIO.28 | 28  | 20  |
+ |     |     |      0v |      |   | 39 || 40 | 0 | IN   | GPIO.29 | 29  | 21  |
+ +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
+ | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
+ +-----+-----+---------+------+---+---Pi 3---+---+------+---------+-----+-----+
+
+  == Hardware connection ==
+    EPD    =>    Raspberry Pi
+  * VCC    ->    3.3
+  * GND    ->    GND
+  * DIN    ->    MOSI
+  * CLK    ->    SCLK
+  * CS     ->    24 (Physical, BCM: CE0, 8)
+  * D/C    ->    22 (Physical, BCM: 25)
+  * RES    ->    11 (Physical, BCM: 17)
+  * BUSY   ->    18 (Physical, BCM: 24)
+  
+    == How to use ==
+    1, open spidev.
+        spi is enabled in config.txt:
+        dtparam=spi=on
+    or in shell:
+        sudo raspi-config
+            - 5 Interfacing Options  Configure connections to peripherals
+                - 5 Interfacing Options  Configure connections to peripherals
+        
+    2, install the Python libraries.
+        sudo apt-get install python-pip 
+        sudo pip install RPi.GPIO
+        sudo pip install spidev
+        sudo apt-get install ttf-wqy-zenhei ttf-wqy-microhei
+
+    3, change the current directory to where the demo files located.
+
+    4, run the demo with: 
+        sudo python main.py
+    # if use python3:
+        sudo python3 main.py
+*/
+