c - LCD 遵循命令但不显示字符

Question

我已经对 Atmega-16 微 Controller 进行了编程，以连接 LM016L LCD 显示器。程序如下:

#include <avr/io.h>
#include <util/delay.h>
#define MrLCDsCrib PORTB
#define DataDir_MrLCDsCrib DDRB
#define MrLCDsControl PORTD
#define DataDir_MrLCDsControl DDRD
#define LightSwitch 5
#define ReadWrite 7
#define BiPolarMood 2

void Check_IF_MrLCD_isBusy(void);
void Peek_A_Boo(void);
void Send_A_Command(unsigned char command);
void Send_A_Character(unsigned char character);

int main(void) {
    DataDir_MrLCDsControl |= 1 << LightSwitch | 1 << ReadWrite | 1 << BiPolarMood;
    _delay_ms(15);

    Send_A_Command(0x01); //Clear Screen 
    _delay_ms(20);
    Send_A_Command(0x38); //8-bit mode
    _delay_ms(20);
    Send_A_Command(0b00001110); // cursor on
    _delay_ms(20);
    Send_A_Command(0x0F); // cursor blinking
    _delay_ms(20);

    Send_A_Character(0x4E); //N
    _delay_ms(20);
    Send_A_Character(0x65); //e
    _delay_ms(20);
    Send_A_Character(0x77); //w
    _delay_ms(20);


    while (1) {}
}

void Check_IF_MrLCD_isBusy() {
    DataDir_MrLCDsCrib = 0;
    MrLCDsControl |= 1 << ReadWrite;
    MrLCDsControl &= ~1 << BiPolarMood;

    while (MrLCDsCrib >= 0x80) {
        Peek_A_Boo();
    }
    DataDir_MrLCDsCrib = 0xFF;
}

//Peek_A_Boo() writes the data to or from the LCD that are waiting to be written 
void Peek_A_Boo() {
    MrLCDsControl |= 1 << LightSwitch;
    asm volatile("nop");
    asm volatile("nop");
    MrLCDsControl &= ~1 << LightSwitch;
}

void Send_A_Command(unsigned char command) {
    Check_IF_MrLCD_isBusy();
    MrLCDsCrib = command;
    MrLCDsControl &= ~ ((1 << ReadWrite) | (1 << BiPolarMood));
    Peek_A_Boo();
    MrLCDsCrib = 0;
}

void Send_A_Character(unsigned char character) {
    Check_IF_MrLCD_isBusy();
    MrLCDsCrib = character;
    MrLCDsControl &= ~ (1 << ReadWrite);
    MrLCDsControl |= 1 << BiPolarMood;
    Peek_A_Boo();
    MrLCDsCrib = 0;
}

当我向 LCD 发送命令(例如使光标闪烁)时，它工作得很好。但是当调用函数Send_A_Character()将字符写入屏幕时，它不起作用。我无法让 LCD 在屏幕上显示任何内容。上面的代码没有语法错误。如果你们中的任何人能够指出导致 LCD 无法在屏幕上显示任何内容的逻辑错误，那就太好了。我什至尝试将每个点的延迟增加到 2 秒，但这没有用。

Answer 1

我在这段代码上花了几个小时，但无法让它工作。不过，我设法在 LCD 上写了一些内容，如下所示:

1. 需要将LCD的RW连接到MCu的GND
2. 同样根据代码修改其他连接。

3. 这是对我有用的代码:(http://circuitdigest.com/microcontroller-projects/lcd-interfacing-with-atmega32-avr)

   // Code for LCD Interfacing with ATmega32 AVR microcontroller
   #include <avr/io.h>
   #define F_CPU 1000000UL
   #include <util/delay.h>
   #define RS 6
   #define E  5
   void send_a_command (unsigned char command);
   void send_a_character(unsigned char character);
   int main(void)
   {
       DDRA = 0xFF;
       DDRD = 0xFF;
       _delay_ms(50);
       send_a_command(0x01);// sending all clear command
       send_a_command(0x38);// 16*2 line LCD
       send_a_command(0x0E);// screen and cursor ON
   
        send_a_character (0x44); // ASCII(American Standard Code for Information Interchange) code for 'D'
        send_a_character (0x49); // ASCII(American Standard Code for Information Interchange) code for 'I'
        send_a_character (0x4C); // ASCII(American Standard Code for Information Interchange) code for 'L'
        send_a_character (0x49); // ASCII(American Standard Code for Information Interchange) code for 'I'
        send_a_character (0x50); // ASCII(American Standard Code for Information Interchange) code for 'P'
   
   }
   void send_a_command (unsigned char command)
   {
       PORTA=command;
       PORTD&= ~(1<<RS);
       PORTD|= (1<<E);
       _delay_ms(50);
       PORTD&= ~(1<<E);
       PORTA =0;
   }
   void send_a_character (unsigned char character)
   {
       PORTA=character;
       PORTD|= (1<<RS);
       PORTD|= (1<<E);
       _delay_ms(50);
       PORTD&= ~(1<<E);
       PORTA =0;
   }