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<>树莓派连接LCD1602液晶显示屏，并显示内容
<>一、效果图
所需要硬件：
* LCD1602液晶显示屏
* IIC转接LCD1602模块（转成IIC通讯）
<>二、设置树莓派，启动IIC通讯功能
* 因为树莓派刚烧录完系统后IIC功能是没有启动的，在命令行分别输入以下命令： raspi-config ; 进入树莓派设置界面 >>>
Interfacing Options; 设置 >>>P5 I2C ; 选择I2C选项 >>>enable ; 启动I2C功能
* 下载对应缺的包，例如： sudo apt-get install i2c-tools sudo apt-get update sudo apt-get
install python3-smbus
* 设置好了，重启一次树莓派。
<>三、连线
* 树莓派-------液晶显示屏
* VCC----------3.3V
* GND-----------地
* SDA----------SDA
* SCL-----------SCL
<>四、代码
方案一：（一个LCD602程序—LCD1602.py）
''' 1602/1602A author：ZengXiaojie description： 直接实例化 My1602 对象 然后调用对象的
print_lcd(param1, param2, str) 方法 ex：print_lcd(0, 0, 'Hello, world!')
param1：从第几位开始，共16位（0-15），超出不显示，除非移动屏幕（其实1602一行有40位） param2：第几行，共有两行，0为第一行，1
位第二行。 str：要显示的数据 每次打印字符时，建议适当清屏。''' import time import smbus import sys class
My1602(object): BUS = smbus.SMBus(1) LCD_ADDR = 0x27 BLEN = 1 # ''' # 开关灯 def
turn_light(self, key): self.BLEN = key if key == 1: self.BUS.write_byte(self.
LCD_ADDR, 0x08) else: self.BUS.write_byte(self.LCD_ADDR, 0x00) # ''' def
write_word(self, addr, data): temp = data if self.BLEN == 1: temp |= 0x08 else:
temp&= 0xF7 self.BUS.write_byte(addr, temp) # 写命令 def send_command(self, comm):
# 发送7-4位数据 buf = comm & 0xF0 buf |= 0x04 # RS = 0, RW = 0, EN = 1 self.
write_word(self.LCD_ADDR, buf) time.sleep(0.002) buf &= 0xFB self.write_word(
self.LCD_ADDR, buf) # 发送3-0位数据 buf = (comm & 0x0F) << 4 buf |= 0x04 # RS = 0, RW
= 0, EN = 1 self.write_word(self.LCD_ADDR, buf) time.sleep(0.002) buf &= 0xFB
self.write_word(self.LCD_ADDR, buf) # 写数据 def send_data(self, data): # 发送7-4位数据
buf= data & 0xF0 buf |= 0x05 # RS = 1, RW = 0, EN = 1 self.write_word(self.
LCD_ADDR, buf) time.sleep(0.002) buf &= 0xFB self.write_word(self.LCD_ADDR, buf)
# 发送3-0位数据 buf = (data & 0x0F) << 4 buf |= 0x05 # RS = 1, RW = 0, EN = 1 self.
write_word(self.LCD_ADDR, buf) time.sleep(0.002) buf &= 0xFB self.write_word(
self.LCD_ADDR, buf) # 初始化 def __init__(self): try: self.send_command(0x33) time.
sleep(0.005) self.send_command(0x32) time.sleep(0.005) self.send_command(0x28)
time.sleep(0.005) self.send_command(0x0C) time.sleep(0.005) self.send_command(
0x01) self.BUS.write_byte(self.LCD_ADDR, 0x08) except: return None else: return
None # 清屏 defclear_lcd(self): self.send_command(0x01) # 清屏 # 显示字符 def print_lcd(
self, x, y, str): if x < 0: x = 0 if x > 15: x = 15 if y < 0: y = 0 if y > 1: y
= 1 addr = 0x80 + 0x40 * y + x self.send_command(addr) for chr in str: self.
send_data(ord(chr)) if __name__ == '__main__': my1602 = My1602() # turn_light(0)
# 关闭背景灯光 my1602.print_lcd(0, 0, 'Hello, world!') my1602.print_lcd(8, 1, 'by
zxj')
方案二：（两个python程序：1.LCD1602驱动程序，2.调用驱动程序）
<>程序1—LCD1602.py(LCD主控制程序)：
import LCD1602 as LCD import time LCD.init_lcd() time.sleep(2) LCD.print_lcd(0,
0,'start')
<>程序2—LCD1602.py（LCD驱动程序1）：
import time import smbus import logx import logging BUS = smbus.SMBus(1)
LCD_ADDR = 0x27 BLEN = 1 #turn on/off background light def turn_light(key):
globalBLEN BLEN = key if key ==1 : BUS.write_byte(LCD_ADDR ,0x08) logging.info(
'LCD executed turn on BLight') else: BUS.write_byte(LCD_ADDR ,0x00) logging.info
('LCD executed turn off BLight') def write_word(addr, data): global BLEN temp =
dataif BLEN == 1: temp |= 0x08 else: temp &= 0xF7 BUS.write_byte(addr ,temp) def
send_command(comm): # Send bit7-4 firstly buf = comm & 0xF0 buf |= 0x04 # RS = 0
, RW = 0, EN = 1 write_word(LCD_ADDR ,buf) time.sleep(0.002) buf &= 0xFB # Make
EN = 0 write_word(LCD_ADDR ,buf) # Send bit3-0 secondly buf = (comm & 0x0F) << 4
buf|= 0x04 # RS = 0, RW = 0, EN = 1 write_word(LCD_ADDR ,buf) time.sleep(0.002)
buf&= 0xFB # Make EN = 0 write_word(LCD_ADDR ,buf) def send_data(data): # Send
bit7-4 firstly buf = data & 0xF0 buf |= 0x05 # RS = 1, RW = 0, EN = 1 write_word
(LCD_ADDR ,buf) time.sleep(0.002) buf &= 0xFB # Make EN = 0 write_word(LCD_ADDR
,buf) # Send bit3-0 secondly buf = (data & 0x0F) << 4 buf |= 0x05 # RS = 1, RW =
0, EN = 1 write_word(LCD_ADDR ,buf) time.sleep(0.002) buf &= 0xFB # Make EN = 0
write_word(LCD_ADDR ,buf) def init_lcd(): try: send_command(0x33) # Must
initialize to8-line mode at first time.sleep(0.005) send_command(0x32) # Then
initialize to4-line mode time.sleep(0.005) send_command(0x28) # 2 Lines & 5*7
dots time.sleep(0.005) send_command(0x0C) # Enable display without cursor time.
sleep(0.005) send_command(0x01) # Clear Screen logging.info('LCD init over') BUS
.write_byte(LCD_ADDR ,0x08) logging.info('LCD turning on BLight') except: return
Falseelse: return True def clear_lcd(): send_command(0x01) # Clear Screen def
print_lcd(x, y, str): if x < 0: x = 0 if x > 15: x = 15 if y <0: y = 0 if y > 1:
y= 1 # Move cursor addr = 0x80 + 0x40 * y + x send_command(addr) for chr in str
: send_data(ord(chr)) if __name__ == '__main__': init_lcd() print_lcd(0, 0,
'Hello, world!') print_lcd(8, 1, 'by Jerry')
<>程序3—logx.py（LCD驱动程序2）：
import logging #print on log file logging.basicConfig(level=logging.INFO,
format='%(asctime)s <%(levelname)s> [line:%(lineno)d] %(filename)s :
%(message)s', datefmt='%Y-%m-%d %H:%M:%S', filename='trace.log', filemode='a')
#w a #print on screem console= logging.StreamHandler() console.setLevel(logging.
DEBUG) formatter = logging.Formatter('%(asctime)s <%(levelname)s>
[line:%(lineno)d] %(filename)s : %(message)s') console.setFormatter(formatter)
logging.getLogger('').addHandler(console) if __name__ == '__main__': #CRITICAL >
ERROR > WARNING > INFO > DEBUG > NOTSET logging.critical('This is critical
message') logging.error('This is error message') logging.warning('This is
warning message') logging.info('This is info message') logging.debug('This is
debug message') #logging.notset('This is notset message')
<>五、运行即可，运行成功如下：