Witajcie!
Mam ostatnio (mówiąc ostatnio mam na myśli 2 tygodnie) bardzo duży problem z moim wyświetlaczem LCD do Raspberry Pi 3.
Żaden znaleziony w necie kod nie działa, wszelkie próby napisania go własnoręcznie legły w gruzach. Pojawił się jednak promyk nadziei - mam kod w Pythonie, który działa. Spróbowałem go przepisać na Javę i spróbować go wykonać.
Hardware
Software
Działający kod w Pythonie
#!/usr/bin/python
import smbus
import time
# Define some device parameters
I2C_ADDR = 0x3f # I2C device address
LCD_WIDTH = 16 # Maximum characters per line
# Define some device constants
LCD_CHR = 1 # Mode - Sending data
LCD_CMD = 0 # Mode - Sending command
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
LCD_BACKLIGHT = 0x08 # On
# LCD_BACKLIGHT = 0x00 # Off
ENABLE = 0b00000100 # Enable bit
# Timing constants
E_PULSE = 0.0005
E_DELAY = 0.0005
# Open I2C interface
# bus = smbus.SMBus(0) # Rev 1 Pi uses 0
bus = smbus.SMBus(1) # Rev 2 Pi uses 1
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 = the data
# mode = 1 for data
# 0 for command
bits_high = mode | (bits & 0xF0) | LCD_BACKLIGHT
bits_low = mode | ((bits << 4) & 0xF0) | LCD_BACKLIGHT
# High bits
bus.write_byte(I2C_ADDR, bits_high)
lcd_toggle_enable(bits_high)
# Low bits
bus.write_byte(I2C_ADDR, bits_low)
lcd_toggle_enable(bits_low)
def lcd_toggle_enable(bits):
# Toggle enable
time.sleep(E_DELAY)
bus.write_byte(I2C_ADDR, (bits | ENABLE))
time.sleep(E_PULSE)
bus.write_byte(I2C_ADDR, (bits & ~ENABLE))
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)
def main():
# Main program block
# Initialise display
lcd_init()
while True:
# Send some test
lcd_string("RPiSpy <", LCD_LINE_1)
lcd_string("I2C LCD <", LCD_LINE_2)
time.sleep(3)
# Send some more text
lcd_string("> RPiSpy", LCD_LINE_1)
lcd_string("> I2C LCD", LCD_LINE_2)
time.sleep(3)
if __name__ == '__main__':
try:
main()
except KeyboardInterrupt:
pass
finally:
lcd_byte(0x01, LCD_CMD)
Prawie działający kod w Javie:
package com.burdzi0;
import com.pi4j.io.i2c.I2CBus;
import com.pi4j.io.i2c.I2CDevice;
import com.pi4j.io.i2c.I2CFactory;
import com.pi4j.io.i2c.I2CFactoryProviderRaspberry;
import com.sun.org.apache.bcel.internal.generic.I2C;
import java.io.IOException;
public class LCDController {
int I2C_ADDR = 0x3f;
int LCD_WIDTH = 16;
int LCD_CHR = 1;
int LCD_CMD = 0;
int LCD_LINE_1 = 0x80;
int LCD_LINE_2 = 0xC0;
int LCD_BACKLIGHT_ON = 0x08;
int LCD_BACKLIGHT_OFF = 0x00;
int ENABLE = 0b00000100;
int E_PULSE = 5;
int E_DELAY = 5;
I2CBus bus;
I2CDevice dev;
public LCDController() throws IOException, InterruptedException {
bus = I2CFactory.getInstance(I2CBus.BUS_1);
dev = bus.getDevice(I2C_ADDR);
init();
}
void init() throws InterruptedException, IOException {
lcd_byte(0x33, LCD_CMD);
lcd_byte(0x32, LCD_CMD);
lcd_byte(0x06, LCD_CMD);
lcd_byte(0x0C, LCD_CMD);
lcd_byte(0x28, LCD_CMD);
lcd_byte(0x01, LCD_CMD);
Thread.sleep(E_DELAY);
}
void lcd_byte(int bits, int mode) throws IOException, InterruptedException {
int bits_high = mode | (bits & 0xF0) | LCD_BACKLIGHT_ON;
int bits_low = mode | ((bits << 4) & 0xF0) | LCD_BACKLIGHT_ON;
dev.write(I2C_ADDR, (byte) bits_high);
lcd_toggle_enable((byte) bits_high);
dev.write(I2C_ADDR, (byte) bits_low);
lcd_toggle_enable((byte) bits_low);
}
void lcd_toggle_enable(byte bits) throws InterruptedException, IOException {
Thread.sleep(E_DELAY);
dev.write(I2C_ADDR, (byte) (bits | ENABLE));
Thread.sleep(E_PULSE);
dev.write(I2C_ADDR, (byte) (bits & ~ENABLE));
Thread.sleep(E_DELAY);
}
void lcd_string(String message, int line) throws IOException, InterruptedException {
lcd_byte(line, LCD_CMD);
for (int i = 0; i < LCD_WIDTH; i++) {
lcd_byte(message.charAt(i), LCD_CHR);
}
}
public static void main(String[] args) {
LCDController lcd = null;
try {
lcd = new LCDController();
lcd.init();
while (true) {
lcd.lcd_string("RPiSpy <", lcd.LCD_LINE_1);
lcd.lcd_string("I2C LCD <", lcd.LCD_LINE_2);
Thread.sleep(3000);
lcd.lcd_string("> RPiSpy", lcd.LCD_LINE_1);
lcd.lcd_string("> I2C LCD", lcd.LCD_LINE_2);
Thread.sleep(3000);
}
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
try {
lcd.lcd_byte(0x01, lcd.LCD_CMD);
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
Wiem, że kod nie jest ładny, ale ma być przede wszystkim funkcjonalny. Efektem tego kodu jest:
Gdzie popełniłem błąd?