avr單片機串行四線驅動1602液晶

示范程序很簡單，不用多注釋應該都能看懂。作為演示用途，其中有些長時間延時沒有沒有使用定時器，在多任務系統(tǒng)中當然要用定時中斷來代替了。
這就是電路，細心的朋友會發(fā)現(xiàn)實物圖中有幾個貼片的阻容件，秘密就在這里，利用電容的記憶效應，把并行的數(shù)據(jù)轉為串行。

關于本制作的更多圖解請打開：http://www.51hei.com/bbs/dpj-20365-1.html
// Drive a LCD1602 with 2 wire
//===================================================
//ICC-AVR application builder : 2010-10-3 19:30:02
// Target : M16
// Crystal: 4.0000Mhz

#include
#include

#define Set_E PORTB|=2
#define Clr_E PORTB&=~2
#define Set_D PORTB|=1
#define Clr_D PORTB&=~1
#define Set_xy(y,x) Send(0,(y<<6)|(x&15)|0x80)

//===================================================
void init_devices(void)
{
CLI(); //disable all interrupts
DDRB = 0x03;
MCUCR = 0x00;
GICR = 0x00;
SEI(); //re-enable interrupts
}

//===================================================
void Delay(unsigned int i)
{
while(i--);
}

//===================================================
void Send(unsigned char RS, unsigned char dat)
{
unsigned char i;
for (i = 2; i > 0; i--)
{
if (dat & 0x80) Set_D; else Clr_D;
Delay(10608);//14520us
if (RS) Set_E;
if (dat & 0x40) Set_D; else Clr_D;
Delay(462); //660us
if (dat & 0x20) Set_D; else Clr_D;
Delay(18); //30us
Set_E;
if (dat & 0x10) Set_D; else Clr_D;
_NOP(); //0.5us < t < 1.36us
Clr_E;
dat <<= 4;
}
}

//===================================================
void init_1602(void)
{
unsigned char i = 3;
Clr_D;
Clr_E;
Delay(10608);
do{
Clr_D;
Delay(462);
Set_D;
Set_E;
Delay(18);
if (i == 0) Clr_D;
_NOP();_NOP();_NOP();
Clr_E;
}while(i--);
Send(0,0x28);
Send(0,0x01);
Send(0,0x0f);
}

//===================================================
void Send_S(unsigned char *p)
{
while(*p) Send(1,*p++);
}

//===================================================
void main(void)
{
unsigned char i;
init_devices();
init_1602();

Set_xy(0,2);
Send_S("Hello world!");
Set_xy(1,3);
Send_S("Im COWBOY.");
for (i=0;i<255;i++) Delay(10000);

Send(0,0x01);
Set_xy(0,3);
Send_S("Welcome to");
Set_xy(1,1);
Send_S(www.51hei.com);
while(1);
}