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1.實驗目的
1.學習在PC機系統中擴展簡單I/O接口的方法。
2.進一步學習編制數據輸出程序的設計方法。
3.學習TPYBoardv202控制OLED顯示字符。
2.所需元器件
TPYBoardv202開發板一塊
數據線一條
杜邦線若干
OLED液晶屏一塊
3.什么是OLED顯示屏
(1)OLED顯示屏簡介
有機發光二極管（organiclight-emittingdiode，OLED）是一種由柯達公司開發并擁有專利的顯示技術，這項技術使用有機聚合材料作為發光二極管中的半導體（semiconductor）材料。聚合材料可以是天然的，也可能是人工合成的，可能尺寸很大，也可能尺寸很小。其廣泛運用于手機、數碼攝像機、DVD機、個人數字助理（PDA）、筆記本電腦、汽車音響和電視。OLED顯示器很薄很輕，因為它不使用背光。
本例中使用0.96寸OLED顯示屏，該屏具有高亮度，低功耗屏，顯示顏色純正，在陽光下有很好的可視效果。模塊供電可以是3.3V也可以是5V，不需要修改模塊電路，同時兼容3種通信方式：4線SPI、3線SPI、IIC，通信模式的選擇可以根據提供的BOM表進行跳選。該模塊一共有三種顏色：藍色、白色、黃藍雙色。OLED屏具有多個控制指令，可以控制OLED的亮度、對比度、開關升壓電路等指令。操作方便，功能豐富。同時為了方便應用在產品上，預留4個M2固定孔，方便用戶固定在機殼上。0.96寸OLED顯示屏的驅動芯片為：SSD1306(已集成在屏中)。
(2)實際顯示效果
(3)OLED接口定義
1>GND=電源地
2>VCC=電源地（2.8V~5.5V）
3>D0=時鐘線
4>D1=數據線
5>RES=復位線
6>DC=數據/命令
7>CS=片選
4.具體接線方法
5.實物接線圖
6.程序源代碼
main.py 程序源代碼
- # main.py -- put your code here!
- import machine
- from machine import Pin,I2C,SPI
- import ssd1306
- import math
- import time
- spi = SPI(baudrate=10000000, polarity=1, phase=0, sck=Pin(14,Pin.OUT), mosi=Pin(13,Pin.OUT), miso=Pin(12))
- display = ssd1306.SSD1306_SPI(128, 64, spi, Pin(5),Pin(4), Pin(16))
- led_blue = machine.Pin(2, Pin.OUT) # 設置 GPIO2 為輸出
- led_blue.high()
- try:
- display.poweron()
- display.init_display()
- display.text('TPYBoard V202',1,1)
- display.text('Hi, TurnipSmart',1,16)
- display.text('I Love You',1,31)
- display.text('This is DNA!!',1,46)
- display.show()
- time.sleep(3)
- display.fill(0)
- #顯示DNA
- for x in range(0, 128):
- display.pixel(x, 32+int(math.cos(x/64*math.pi)*30 +2), 1)
- display.pixel(x, 32+int(math.cos((x+64)/64*math.pi)*30+2), 1)
- display.show()
- except Exception as ex:
- led_blue.low()
- print('Unexpected error: {0}'.format(ex))
- display.poweroff()
ssd1306程序源代碼
- import pyb
- import font
- # Constants
- DISPLAYOFF = 0xAE
- SETCONTRAST = 0x81
- DISPLAYALLON_RESUME = 0xA4
- DISPLAYALLON = 0xA5
- NORMALDISPLAY = 0xA6
- INVERTDISPLAY = 0xA7
- DISPLAYON = 0xAF
- SETDISPLAYOFFSET = 0xD3
- SETCOMPINS = 0xDA
- SETVCOMDETECT = 0xDB
- SETDISPLAYCLOCKDIV = 0xD5
- SETPRECHARGE = 0xD9
- SETMULTIPLEX = 0xA8
- SETLOWCOLUMN = 0x00
- SETHIGHCOLUMN = 0x10
- SETSTARTLINE = 0x40
- MEMORYMODE = 0x20
- COLUMNADDR = 0x21
- PAGEADDR = 0x22
- COMSCANINC = 0xC0
- COMSCANDEC = 0xC8
- SEGREMAP = 0xA0
- CHARGEPUMP = 0x8D
- EXTERNALVCC = 0x10
- SWITCHCAPVCC = 0x20
- SETPAGEADDR = 0xB0
- SETCOLADDR_LOW = 0x00
- SETCOLADDR_HIGH = 0x10
- ACTIVATE_SCROLL = 0x2F
- DEACTIVATE_SCROLL = 0x2E
- SET_VERTICAL_SCROLL_AREA = 0xA3
- RIGHT_HORIZONTAL_SCROLL = 0x26
- LEFT_HORIZONTAL_SCROLL = 0x27
- VERTICAL_AND_RIGHT_HORIZONTAL_SCROLL = 0x29
- VERTICAL_AND_LEFT_HORIZONTAL_SCROLL = 0x2A
- # I2C devices are accessed through a Device ID. This is a 7-bit
- # value but is sometimes expressed left-shifted by 1 as an 8-bit value.
- # A pin on SSD1306 allows it to respond to ID 0x3C or 0x3D. The board
- # I bought from ebay used a 0-ohm resistor to select between "0x78"
- # (0x3c << 1) or "0x7a" (0x3d << 1). The default was set to "0x78"
- DEVID = 0x3c
- # I2C communication here is either <DEVID> <CTL_CMD> <command byte>
- # or <DEVID> <CTL_DAT> <display buffer bytes> <> <> <> <>...
- # These two values encode the Co (Continuation) bit as b7 and the
- # D/C# (Data/Command Selection) bit as b6.
- CTL_CMD = 0x80
- CTL_DAT = 0x40
- class SSD1306(object):
- def __init__(self, pinout, height=32, external_vcc=True, i2c_devid=DEVID):
- self.external_vcc = external_vcc
- self.height = 32 if height == 32 else 64
- self.pages = int(self.height / 8)
- self.columns = 128
- # Infer interface type from entries in pinout{}
- if 'dc' in pinout:
- # SPI
- rate = 16 * 1024 * 1024
- self.spi = pyb.SPI(1, pyb.SPI.MASTER, baudrate=rate, polarity=1, phase=0) # SCK: Y6: MOSI: Y8
- self.dc = pyb.Pin(pinout['dc'], pyb.Pin.OUT_PP, pyb.Pin.PULL_DOWN)
- self.res = pyb.Pin(pinout['res'], pyb.Pin.OUT_PP, pyb.Pin.PULL_DOWN)
- self.offset = 0
- else:
- # Infer bus number from pin
- if pinout['sda'] == 'X10':
- self.i2c = pyb.I2C(1)
- else:
- self.i2c = pyb.I2C(2)
- self.i2c.init(pyb.I2C.MASTER, baudrate=400000) # 400kHz
- self.devid = i2c_devid
- # used to reserve an extra byte in the image buffer AND as a way to
- # infer the interface type
- self.offset = 1
- # I2C command buffer
- self.cbuffer = bytearray(2)
- self.cbuffer[0] = CTL_CMD
- def clear(self):
- self.buffer = bytearray(self.offset + self.pages * self.columns)
- if self.offset == 1:
- self.buffer[0] = CTL_DAT
- def write_command(self, command_byte):
- if self.offset == 1:
- self.cbuffer[1] = command_byte
- self.i2c.send(self.cbuffer, addr=self.devid, timeout=5000)
- else:
- self.dc.low()
- self.spi.send(command_byte)
- def invert_display(self, invert):
- self.write_command(INVERTDISPLAY if invert else NORMALDISPLAY)
- def display(self):
- self.write_command(COLUMNADDR)
- self.write_command(0)
- self.write_command(self.columns - 1)
- self.write_command(PAGEADDR)
- self.write_command(0)
- self.write_command(self.pages - 1)
- if self.offset == 1:
- self.i2c.send(self.buffer, addr=self.devid, timeout=5000)
- else:
- self.dc.high()
- self.spi.send(self.buffer)
- def set_pixel(self, x, y, state):
- index = x + (int(y / 8) * self.columns)
- if state:
- self.buffer[self.offset + index] |= (1 << (y & 7))
- else:
- self.buffer[self.offset + index] &= ~(1 << (y & 7))
- def init_display(self):
- chargepump = 0x10 if self.external_vcc else 0x14
- precharge = 0x22 if self.external_vcc else 0xf1
- multiplex = 0x1f if self.height == 32 else 0x3f
- compins = 0x02 if self.height == 32 else 0x12
- contrast = 0xff # 0x8f if self.height == 32 else (0x9f if self.external_vcc else 0x9f)
- data = [DISPLAYOFF,
- SETDISPLAYCLOCKDIV, 0x80,
- SETMULTIPLEX, multiplex,
- SETDISPLAYOFFSET, 0x00,
- SETSTARTLINE | 0x00,
- CHARGEPUMP, chargepump,
- MEMORYMODE, 0x00,
- SEGREMAP | 0x10,
- COMSCANDEC,
- SETCOMPINS, compins,
- SETCONTRAST, contrast,
- SETPRECHARGE, precharge,
- SETVCOMDETECT, 0x40,
- DISPLAYALLON_RESUME,
- NORMALDISPLAY,
- DISPLAYON]
- for item in data:
- self.write_command(item)
- self.clear()
- self.display()
- def poweron(self):
- if self.offset == 1:
- pyb.delay(10)
- else:
- self.res.high()
- pyb.delay(1)
- self.res.low()
- pyb.delay(10)
- self.res.high()
- pyb.delay(10)
- def poweroff(self):
- self.write_command(DISPLAYOFF)
- def contrast(self, contrast):
- self.write_command(SETCONTRAST)
- self.write_command(contrast)
- def draw_text(self, x, y, string, size=1, space=1):
- def pixel_x(char_number, char_column, point_row):
- char_offset = x + char_number * size * font.cols + space * char_number
- pixel_offset = char_offset + char_column * size + point_row
- return self.columns - pixel_offset
- def pixel_y(char_row, point_column):
- char_offset = y + char_row * size
- return char_offset + point_column
- def pixel_mask(char, char_column, char_row):
- char_index_offset = ord(char) * font.cols
- return font.bytes[char_index_offset + char_column] >> char_row & 0x1
- pixels = (
- (pixel_x(char_number, char_column, point_row),
- pixel_y(char_row, point_column),
- pixel_mask(char, char_column, char_row))
- for char_number, char in enumerate(string)
- for char_column in range(font.cols)
- for char_row in range(font.rows)
- for point_column in range(size)
- for point_row in range(1, size + 1))
- for pixel in pixels:
- self.set_pixel(*pixel)
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