我创建了一个python程序,使用wxpython
模块显示mcp3008的输出,mcp3008将雨量传感器的模拟数据转换为数字数据。我正在做的这个项目是升级目前的项目只显示数据通过液晶显示20x4从其他输入或来源。但是我的wxpython
程序使用了GPIO08
管脚,它对spi总线有SPIO_CE0_N
功能,因为我的mcp3008
要求它检查我的另一个spi管脚。这是我的mcp3008引脚布局图:
VDD 3.3V
VREF 3.3V
AGND GROUND
CLK GPIO11 (P1-23)
DOUT GPIO9 (P1-21)
DIN GPIO10 (P1-19)
CS GPIO8 (P1-24)
DGND GROUND
PBERY和RASBERY lcd的布局如下:
^{pr2}$作为我从互联网上获得的液晶显示器的python程序,在程序中使用GPIO 08
:
#!/usr/bin/python
#--------------------------------------
# ___ ___ _ ____
# / _ \/ _ \(_) __/__ __ __
# / , _/ ___/ /\ \/ _ \/ // /
# /_/|_/_/ /_/___/ .__/\_, /
# /_/ /___/
#
# lcd_16x2.py
# 20x4 LCD Test Script with
# backlight control and text justification
#
# Author : Matt Hawkins
# Date : 06/04/2015
#
# http://www.raspberrypi-spy.co.uk/
#
#--------------------------------------
# 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
LED_ON = 15
# Define some device constants
LCD_WIDTH = 20 # 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
LCD_LINE_3 = 0x94 # LCD RAM address for the 3rd line
LCD_LINE_4 = 0xD4 # LCD RAM address for the 4th line
# Timing constants
E_PULSE = 0.0005
E_DELAY = 0.0005
def main():
# Main program block
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
GPIO.setup(LED_ON, GPIO.OUT) # Backlight enable
# Initialise display
lcd_init()
# Toggle backlight on-off-on
lcd_backlight(True)
time.sleep(0.5)
lcd_backlight(False)
time.sleep(0.5)
lcd_backlight(True)
time.sleep(0.5)
while True:
# Send some centred test
lcd_string("--------------------",LCD_LINE_1,2)
lcd_string("Rasbperry Pi",LCD_LINE_2,2)
lcd_string("Model B",LCD_LINE_3,2)
lcd_string("--------------------",LCD_LINE_4,2)
time.sleep(3) # 3 second delay
lcd_string("Raspberrypi-spy",LCD_LINE_1,3)
lcd_string(".co.uk",LCD_LINE_2,3)
lcd_string("",LCD_LINE_3,2)
lcd_string("20x4 LCD Module Test",LCD_LINE_4,2)
time.sleep(3) # 20 second delay
# Blank display
lcd_byte(0x01, LCD_CMD)
time.sleep(3) # 3 second delay
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,style):
# Send string to display
# style=1 Left justified
# style=2 Centred
# style=3 Right justified
if style==1:
message = message.ljust(LCD_WIDTH," ")
elif style==2:
message = message.center(LCD_WIDTH," ")
elif style==3:
message = message.rjust(LCD_WIDTH," ")
lcd_byte(line, LCD_CMD)
for i in range(LCD_WIDTH):
lcd_byte(ord(message[i]),LCD_CHR)
def lcd_backlight(flag):
# Toggle backlight on-off-on
GPIO.output(LED_ON, flag)
if __name__ == '__main__':
try:
main()
except keyboardInterrupt:
pass
finally:
lcd_byte(0x01, LCD_CMD)
lcd_string("Goodbye!",LCD_LINE_1,2)
GPIO.cleanup()
所以我的问题是,我能否将使用GPIO 08
的lcd显示的pin更改为其他pin,并将程序更改为使用正在更改的RPi pin,因为我不知道lcd display python程序是否需要在GPIO 08
中使用SPIO_CE0_N
,还是只使用GPIO 08
而不使用SPIO_CE0_N
函数。在
只有在使用硬件SPI的情况下,才能在Raspberry Pi上将
GPIO 8
用于SPI_CE0
,并且从您的MCP3008
连接中,可以很清楚地看到您是。在最简单的解决方案是将}管脚连接到任何其他免费的数字GPIO管脚上,并使用您的
Software SPI
用于MCP3008
,并将MCP3008CLK
、DOUT
、DIN
、和{GPIO08
作为LCD连接。或者你可以做相反的事情,使用软件SPI为你的液晶显示器。在从硬件SPI切换到软件SPI很容易,只需更改代码中的管脚号。您可以在这里阅读有关使用
MCP3008
的软件SPI的更多详细信息,https://learn.adafruit.com/raspberry-pi-analog-to-digital-converters/mcp3008#software-spiGPIO图像供将来参考
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