Python 几秒钟后Raspberry Pi 16x2 LCD屏幕出现故障
我有一个16x2的LCD屏幕,显示实时的时间和日期。问题是,它在启动时会自动启动,但启动时会出现故障 在rc.local中,我添加了一行代码(sleep 10;python/home/pi/Document/LCD.py) 这将在启动时启动它。我认为这个过程开始得太早了。还有一件事让我相信,当我插上显示屏电缆时,它的成功率更高。也许它延迟的过程足以让GPIO引脚初始化?我尝试将其添加为系统服务,但似乎不起作用 我的代码:Python 几秒钟后Raspberry Pi 16x2 LCD屏幕出现故障,python,raspberry-pi,zero,lcd,Python,Raspberry Pi,Zero,Lcd,我有一个16x2的LCD屏幕,显示实时的时间和日期。问题是,它在启动时会自动启动,但启动时会出现故障 在rc.local中,我添加了一行代码(sleep 10;python/home/pi/Document/LCD.py) 这将在启动时启动它。我认为这个过程开始得太早了。还有一件事让我相信,当我插上显示屏电缆时,它的成功率更高。也许它延迟的过程足以让GPIO引脚初始化?我尝试将其添加为系统服务,但似乎不起作用 我的代码: # The wiring for the LCD is as follo
# The wiring for the LCD is as follows:
# 1 : GND
# 2 : 5V
# 3 : Contrast (0-5V)*
# 4 : RS (Register Select)
# 5 : R/W (Read Write) - GROUND THIS PIN
# 6 : Enable or Strobe
# 7 : Data Bit 0 - NOT USED
# 8 : Data Bit 1 - NOT USED
# 9 : Data Bit 2 - NOT USED
# 10: Data Bit 3 - NOT USED
# 11: Data Bit 4
# 12: Data Bit 5
# 13: Data Bit 6
# 14: Data Bit 7
# 15: LCD Backlight +5V**
# 16: LCD Backlight GND
#import
import RPi.GPIO as GPIO
import time
# Define GPIO to LCD mapping
LCD_RS = 7
LCD_E = 8
LCD_D4 = 25
LCD_D5 = 24
LCD_D6 = 23
LCD_D7 = 18
# Define some device constants
LCD_WIDTH = 16 # Maximum characters per line
LCD_CHR = True
LCD_CMD = False
LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line
LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line
# Timing constants
E_PULSE = 0.0005
E_DELAY = 0.0005
def main():
# Main program block
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM) # Use BCM GPIO numbers
GPIO.setup(LCD_E, GPIO.OUT) # E
GPIO.setup(LCD_RS, GPIO.OUT) # RS
GPIO.setup(LCD_D4, GPIO.OUT) # DB4
GPIO.setup(LCD_D5, GPIO.OUT) # DB5
GPIO.setup(LCD_D6, GPIO.OUT) # DB6
GPIO.setup(LCD_D7, GPIO.OUT) # DB7
# Initialise display
lcd_init()
while True:
e = time.strftime("%H:%M:%S")
date = time.strftime("%Y:%m:%d")
# Send some test
lcd_string(date,LCD_LINE_1) #Change 'text' to what you want.
lcd_string(e,LCD_LINE_2)
def lcd_init():
# Initialise display
lcd_byte(0x33,LCD_CMD) # 110011 Initialise
lcd_byte(0x32,LCD_CMD) # 110010 Initialise
lcd_byte(0x06,LCD_CMD) # 000110 Cursor move direction
lcd_byte(0x0C,LCD_CMD) # 001100 Display On,Cursor Off, Blink Off
lcd_byte(0x28,LCD_CMD) # 101000 Data length, number of lines, font size
lcd_byte(0x01,LCD_CMD) # 000001 Clear display
time.sleep(E_DELAY)
def lcd_byte(bits, mode):
# Send byte to data pins
# bits = data
# mode = True for character
# False for command
GPIO.output(LCD_RS, mode) # RS
# High bits
GPIO.output(LCD_D4, False)
GPIO.output(LCD_D5, False)
GPIO.output(LCD_D6, False)
GPIO.output(LCD_D7, False)
if bits&0x10==0x10:
GPIO.output(LCD_D4, True)
if bits&0x20==0x20:
GPIO.output(LCD_D5, True)
if bits&0x40==0x40:
GPIO.output(LCD_D6, True)
if bits&0x80==0x80:
GPIO.output(LCD_D7, True)
# Toggle 'Enable' pin
lcd_toggle_enable()
# Low bits
GPIO.output(LCD_D4, False)
GPIO.output(LCD_D5, False)
GPIO.output(LCD_D6, False)
GPIO.output(LCD_D7, False)
if bits&0x01==0x01:
GPIO.output(LCD_D4, True)
if bits&0x02==0x02:
GPIO.output(LCD_D5, True)
if bits&0x04==0x04:
GPIO.output(LCD_D6, True)
if bits&0x08==0x08:
GPIO.output(LCD_D7, True)
# Toggle 'Enable' pin
lcd_toggle_enable()
def lcd_toggle_enable():
# Toggle enable
time.sleep(E_DELAY)
GPIO.output(LCD_E, True)
time.sleep(E_PULSE)
GPIO.output(LCD_E, False)
time.sleep(E_DELAY)
def lcd_string(message,line):
# Send string to display
message = message.ljust(LCD_WIDTH," ")
lcd_byte(line, LCD_CMD)
for i in range(LCD_WIDTH):
lcd_byte(ord(message[i]),LCD_CHR)
if __name__ == '__main__':
try:
main()
except KeyboardInterrupt:
pass
finally:
lcd_byte(0x01, LCD_CMD)
lcd_string("Goodbye!",LCD_LINE_1)
GPIO.cleanup()
提前谢谢。我看到三个问题
GPIO.cleanup()
将Pi上的任何输出引脚重置为输入。这将使显示器上的输入浮动,这将导致意外行为我使用的是树莓皮零点,使用的是5伏引脚,这是否意味着它将获得5伏电压?这只为VCC提供5伏电压。其他输入仍然具有3.3V或更低的逻辑高电平。抱歉,我一直处于非活动状态,电平转换器需要一段时间才能实现-国际运输缓慢。我已经把它们连接好了,它们工作正常(用伏特计测试),用560欧姆的电阻把e引脚拉低,并去掉了gpio.cleanup()。但是,当我启动它时,背光会亮起,但不会显示任何文本?