前一阵用废旧的树莓派做了一个NAS服务器，手里还要一块闲置的LCD 1602 液晶屏模块，可以用来实时显示IP，作为NAS的服务器输出显示。

在树莓派上LCD 1602 液晶屏模块的使用非常简单，可以用 I2C 方式的驱动，只要使能0，5V，tx,tf四根线就可实现使能，屏幕上自带调压电阻可以调整亮度对比度。极大的简化LED接线和驱动使用。带 I2C 模块的 1602 屏幕背面如图所示。

第一步，线序超级简单，不要接错了。

GND — GND
VCC — 接树莓派 5V
SDA — I2C 数据
SCL — I2C 时钟

第二步，启用树莓派的I2C功能。

sudo apt-get install -y python-smbus
sudo apt-get install -y i2c-tools

第三步，使能I2C
sudo raspi-config
选择I2C

第四步，用 Python 控制 LCD1602 显示需要的信息。

平时用来显示时间的程序代码例 测试程序test.py：

import smbus
import time
import sys
import LCD1602 as LCDif __name__ == '__main__':  LCD.init_lcd()time.sleep(1)LCD.print_lcd(2, 0, '测试程序test')for x in xrange(1, 4):LCD.turn_light(0)LCD.print_lcd(4, 1, 'LIGHT OFF')time.sleep(0.5)LCD.turn_light(1)LCD.print_lcd(4, 1, 'LIGHT ON ')time.sleep(0.5)LCD.turn_light(0)while True:now = time.strftime('%m/%d %H:%M:%S', time.localtime(time.time()))LCD.print_lcd(1, 1, now)time.sleep(0.2)

注意1，LCD1602模块不显示可以调整一下电阻，亮度太高也不行的。
注意2，LCD1602驱动在程序里作为一个python导入模块使用。找不到的，用我下面共享的，保存为LCD1602.py作为驱动和程序放在同目录即可。怎么样开机自动运行参考我的另一篇文章：树莓派Python程序开机自启动（Linux下Python程序开机自启动）

LCD1602.py驱动程序代码

import time
import smbus
BUS = smbus.SMBus(1)
LCD_ADDR = 0x27
BLEN = 1 #turn on/off background lightdef turn_light(key):global BLENBLEN = keyif key ==1 :BUS.write_byte(LCD_ADDR ,0x08)else:BUS.write_byte(LCD_ADDR ,0x00)def write_word(addr, data):global BLENtemp = dataif BLEN == 1:temp |= 0x08else:temp &= 0xF7BUS.write_byte(addr ,temp)def send_command(comm):# Send bit7-4 firstlybuf = comm & 0xF0buf |= 0x04               # RS = 0, RW = 0, EN = 1write_word(LCD_ADDR ,buf)time.sleep(0.002)buf &= 0xFB               # Make EN = 0write_word(LCD_ADDR ,buf)# Send bit3-0 secondlybuf = (comm & 0x0F) << 4buf |= 0x04               # RS = 0, RW = 0, EN = 1write_word(LCD_ADDR ,buf)time.sleep(0.002)buf &= 0xFB               # Make EN = 0write_word(LCD_ADDR ,buf)def send_data(data):# Send bit7-4 firstlybuf = data & 0xF0buf |= 0x05               # RS = 1, RW = 0, EN = 1write_word(LCD_ADDR ,buf)time.sleep(0.002)buf &= 0xFB               # Make EN = 0write_word(LCD_ADDR ,buf)# Send bit3-0 secondlybuf = (data & 0x0F) << 4buf |= 0x05               # RS = 1, RW = 0, EN = 1write_word(LCD_ADDR ,buf)time.sleep(0.002)buf &= 0xFB               # Make EN = 0write_word(LCD_ADDR ,buf)def init_lcd():try:send_command(0x33) # Must initialize to 8-line mode at firsttime.sleep(0.005)send_command(0x32) # Then initialize to 4-line modetime.sleep(0.005)send_command(0x28) # 2 Lines & 5*7 dotstime.sleep(0.005)send_command(0x0C) # Enable display without cursortime.sleep(0.005)send_command(0x01) # Clear ScreenBUS.write_byte(LCD_ADDR ,0x08)except:return Falseelse:return Truedef clear_lcd():send_command(0x01) # Clear Screendef print_lcd(x, y, str):if x < 0:x = 0if x > 15:x = 15if y <0:y = 0if y > 1:y = 1# Move cursoraddr = 0x80 + 0x40 * y + xsend_command(addr)for chr in str:send_data(ord(chr))if __name__ == '__main__':init_lcd()print_lcd(0, 0, 'Hello, world!')```