16 * 2键盘和LCD与atmega32接口

时间:2018-10-18 19:51:17

标签: embedded avr lcd keypad atmega16

我对一个键盘模块有一个令人失望的问题,当按下它的任何键时,它通常会显示LCD模块上按下的键。问题是,只要我的应用程序(例如要接收密码的系统并显示在LCD上),每当我按下该键时,行都将停止扫描,并且我无法按任何其他键在LCD上显示。如果我想在LCD上显示列表,并且想在屏幕上翻一页以恢复显示列表,那么我现在面临的另一个问题。我该如何实现呢? 我将为原理图添加屏幕截图,并同时提供要检查的键盘和LCD的代码。还是感谢您对我的帮助。 enter image description here

我的应用代码:

#define F_CPU 8000000UL
#include <util/delay.h>
#include <avr/io.h>
#include "LCD.h"
#include "Keypad.h"

int main(void)
{
    /* Replace with your application code */
    uint8_t keypadPress = 0;
    Keypad_vInit();
    LCD_vInit();

    while( !Keypad_u8Scan() )
    {
        keypadPress = Keypad_u8Scan();
        if( keypadPress == '8' )
        {
            LCD_vPrintChar( '8' );
            while( keypadPress == '8' );
        }
    }
}

我的LCD库:

#if defined MODE_4

static void sendFallingEdge( void ); /* This prototype is declared static       to avoid modifying it. */

static void sendFallingEdge( void )
{
    /* Initializing the EN pin of the LCD when detecting a falling edge. */
    /* The following code is the representation of falling edge using the   system clock. */
    PORTB |= ( 1 << EN );
    _delay_ms( 1 );
    PORTB &= ( ~ ( 1 << EN ) );
    _delay_ms( 1 );
}

void LCD_vSendCmd( char cmd )
{
    /* Transferring the first nibble. */
    PORTA &= 0x0F;
    PORTA |= ( cmd & 0xF0 );
    CLR_BIT( PORTB, RS ); /* Transferring instructions data. */
    sendFallingEdge( );

    /* Transferring the second nibble. */
    PORTA &= 0x0F;
    PORTA |= ( cmd << 4 );
    CLR_BIT( PORTB, RS ); /* Transferring instructions data. */
    sendFallingEdge( );
}

void LCD_vInit( void )
{
    DDRA |= 0xF0; /* DDRA |= 0b11110000; */
    DDRB |= 0x0E; /* DDRB |= 0b00001110; */ /* Those three HIGH bits are the RS, RW and EN respectively. */
    CLR_BIT( PORTB, RW ); /* Write mode enabled according to the LCD's datasheet. */

    LCD_vSendCmd( 0x33 );
    _delay_ms( 1 );

    LCD_vSendCmd( 0x32 );
    _delay_ms( 1 );

    LCD_vSendCmd( 0x28 );
    _delay_ms( 1 );

    LCD_vSendCmd( 0x01 );
    _delay_ms( 1 );

    LCD_vSendCmd( 0x0F );
    _delay_ms( 1 );
}

void LCD_vPrintChar( char data )
{
    PORTA &= 0x0F;
    PORTA |= ( data & 0xF0 );
    SET_BIT( PORTB, RS ); /* Transferring display data. */
    sendFallingEdge( );

    PORTA &= 0x0F;
    PORTA |= ( data << 4 ); 
    SET_BIT( PORTB, RS ); /* Transferring display data. */
    sendFallingEdge( );
}

void LCD_vPrintString( char * str )
{
    uint8_t counter;
    for( counter = 0; str[ counter ] != '\0'; counter ++ )
    {
        LCD_vPrintChar( str[ counter ] );
    }
}

void LCD_vPrintNumbers( uint8_t str[ ], uint8_t size )
{
    uint8_t counter;
    for( counter = 0; str[ counter ] < size; counter ++ )
    {
        LCD_vPrintChar( str[ counter ] );
    }
}

void LCD_vClrScreen( void )
{
    LCD_vSendCmd( CLR_SCRN );
}

void LCD_vMoveCursor( char row, char column )
{
    char cmd;
    if( row == 1 )
    {
        cmd = STARTROW0 + column - 1;
        LCD_vSendCmd( cmd );
    }
    else if( row == 2 )
    {
        cmd = STARTROW1 + column - 1;
        LCD_vSendCmd( cmd );
    }
}

#endif

我的键盘库:

#include <avr/io.h>
#include "std_macros.h"

void Keypad_vInit( void )
{
    DDRC = 0x0F; 
    CLR_BIT( SFIOR, PUD ); 
    PORTC = 0xFF;          
}
unsigned char Keypad_u8Scan( void )
{
    unsigned char row, column, scan, buttonPressed = 0;
    unsigned char KP[ 4 ][ 4 ] = { { '7', '8', '9', '/' },
                                   { '4', '5', '6', '*' },
                                   { '1', '2', '3', '-' },
                                   { ' ', '0', '=', '+' }           
                                 };
    for( row = 0; row < 4; row ++ )
    {
        PORTC |= 0x0F;
        CLR_BIT( PORTC, row );
        for( column = 4; column < 8; column ++ )
        {
            scan = READ_BIT( PINC, column );
            if( scan == 0 )
            {
                buttonPressed = KP[ row ][ column - 4 ];
            }
        }
    }
    return buttonPressed;
}

最后是我的标准宏:

#define SET_BIT( REGISTER, BIT_NUM ) ( REGISTER = REGISTER | ( 1 << BIT_NUM ) )
#define CLR_BIT( REGISTER, BIT_NUM ) ( REGISTER = REGISTER & ( ~( 1 << BIT_NUM ) ) )

2 个答案:

答案 0 :(得分:1)

while为假时,您的!Keypad_u8Scan()循环终止,然后main()终止。当按下8以外的任何键时,会发生这种情况,因为只有在键为8的情况下,您才等待释放键。

在任何“大循环”调度嵌入式系统中,main()通常不应终止-外循环应是不确定的。

以下调度循环将起作用(假设键盘和LCD功能起作用),并且更容易扩展-添加额外的按下事件处理程序只需在{{上添加一个新的case块1}}:

switch

也许更好的结构是拥有一个单独的函数,该函数等待按下事件,如下所示:

for(;;) // forever
{
    // Wait for key-down
    do
    {
        keypadPress = Keypad_u8Scan();

    } while( keypadPress == 0 ) ;

    // Process key
    switch( keypadPress )
    {
        case '8' :
        {
            LCD_vPrintChar( '8' );
        }
        break ;

        default :
        {
            // any other key not explicitly handled
        }
    }

    // Wait for key-up
    while( Keypad_u8Scan() != 0 )
    {
        // do nothing
    }
}

然后您的主循环可以变得更加简单:

uint8_t getKey()
{
    uint8_t key = 0 ;

    // Wait for key release if pressed on entry
    while( Keypad_u8Scan() != 0 )
    {
        // do nothing          
    } 

    // Wait for new key press
    do
    {
        key = Keypad_u8Scan();

    } while( key == 0 ) ;

    return key ;
}

答案 1 :(得分:0)

当前,您的while循环正在循环,而没有按下任何键:

while( !Keypad_u8Scan() )

它应该永远循环下去。

其后一行:

keypadPress = Keypad_u8Scan();

正在获取按键,并且固定while循环后,它将接收多个按键,因此可以处理页面按钮并显示不同的页面。