1.学习在PC机系统中扩展简单I/O接口的方法。
2.进一步学习编制数据输出程序的设计方法。
3.学习TPYBoardv202控制OLED显示字符。
2.所需元器件
TPYBoardv202开发板一块
数据线一条
杜邦线若干
OLED液晶屏一块
3.什么是OLED显示屏
(1)OLED显示屏简介
有机发光二极管(organiclight-emittingdiode,OLED)是一种由柯达公司开发并拥有专利的显示技术,这项技术使用有机聚合材料作为发光二极管中的半导体(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。其广泛运用于手机、数码摄像机、DVD机、个人数字助理(PDA)、笔记本电脑、汽车音响和电视。OLED显示器很薄很轻,因为它不使用背光。
本例中使用0.96寸OLED显示屏,该屏具有高亮度,低功耗屏,显示颜色纯正,在阳光下有很好的可视效果。模块供电可以是3.3V也可以是5V,不需要修改模块电路,同时兼容3种通信方式:4线SPI、3线SPI、IIC,通信模式的选择可以根据提供的BOM表进行跳选。该模块一共有三种颜色:蓝色、白色、黄蓝双色。OLED屏具有多个控制指令,可以控制OLED的亮度、对比度、开关升压电路等指令。操作方便,功能丰富。同时为了方便应用在产品上,预留4个M2固定孔,方便用户固定在机壳上。0.96寸OLED显示屏的驱动芯片为:SSD1306(已集成在屏中)。
(2)实际显示效果
1>GND=电源地
2>VCC=电源地(2.8V~5.5V)
3>D0=时钟线
4>D1=数据线
5>RES=复位线
6>DC=数据/命令
7>CS=片选
4.具体接线方法
TPYboard v202 |
OLED |
GND |
GND |
3.3V |
VCC |
SCK |
D0 |
MO |
D1 |
G4 |
RES |
G5 |
DC |
G16 |
CS |
5.实物接线图
6.程序源代码
main.py 程序源代码
# 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) # 设置 GPIO2 为输出 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) #显示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程序源代码
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)