S3C2440 进行微秒级、毫秒级延时函数

/******************************************************
*说 明：S3C2440 进行微秒级、毫秒级延时函数
******************************************************/

MCLK:405MHz

HCLK:135MHz

PCLK:67.5MHz

在这里定时器时钟频率为PCLK/8=67.5/8=8.4375MHz

定时器0示例代码：

1 void T0DelayNus(UINT16 t)
 2 {
 3  rTCFG1 &= ~0x0F;
 4  rTCFG1 |= 2;          
 5  rTCNTB0 =(S3C2440PCLK)/8/1000000; //时钟频率为PCLK/8
 6                   //除以1000000表示进行微秒级延时   
 7   rTCON &= ~0x0F;
 8  rTCON |= (1<<3)|(1<<1)|(1<<0);
 9  rTCON &= ~(1<<1);
10 
11 
12  while(t--)
13  {
14    while(rTCNTO0!=(rTCNTB0-1)); 
15  }
16 
17  rTCON &= ~(1<<0);       //停止定时器0
18 
19 }
20 
21 void T0DelayNms(UINT16 t)
22 {
23  rTCFG1 &= ~0x0F;
24  rTCFG1 |= 2;          
25  rTCNTB0 =(S3C2440PCLK)/8/1000; //时钟频率为PCLK/8
26                  //除以1000表示进行毫级延时
27   rTCON &= ~0x0F;
28  rTCON |= (1<<3)|(1<<1)|(1<<0);
29  rTCON &= ~(1<<1);
30 
31  while(t--)
32  {
33    while(rTCNTO0!=(rTCNTB0-1));
34  }
35 
36  rTCON &= ~(1<<0);        //停止定时器0
37 }

定时器1示例代码：

1 void T1DelayNus(UINT16 t)
 2 {
 3  rTCFG1 &= ~(0x0F<<4);
 4  rTCFG1 |= (2<<4);          
 5  rTCNTB1 =(S3C2440PCLK)/8/1000000;   
 6  rTCON &= ~(0x0F<<8);
 7  rTCON |= (1<<11)|(1<<9)|(1<<8);
 8  rTCON &= ~(1<<9);
 9 
10 
11  while(t--)
12  {
13 
14    while(rTCNTO1!=(rTCNTB1-1)); 
15 
16  }
17 
18  rTCON &= ~(1<<8);
19 
20 }
21 
22 
23 void T1DelayNms(UINT16 t)
24 {
25  rTCFG1 &= ~(0x0F<<4);
26  rTCFG1 |= (2<<4);          
27  rTCNTB1 =(S3C2440PCLK)/8/1000;   
28  rTCON &= ~(0x0F<<8);
29  rTCON |= (1<<11)|(1<<9)|(1<<8);
30  rTCON &= ~(1<<9);
31 
32 
33  while(t--)
34  {
35    while(rTCNTO1!=(rTCNTB1-1)); 
36  }
37 
38  rTCON &= ~(1<<8);
39 
40 }

特别是要注意rTCNTOn与rTCNTBn的关系。