ARM裸机IIC例程中的疑惑（各位看官进来看看）

wlh_yuer

ARM裸机IIC例程中的疑惑（各位看官进来看看） [复制链接]

关于ARM裸机IIC例程中的疑惑：
write数据函数中，为什么会有POLLACK模式？（此时所有数据已经发送完了，再来判断ACK）
望大神解惑！谢谢！！！

1. /****************************************************************
   
2. *                  ARMSYS S3C44B0X  IIc At24Cxx TEST                                                *  
   
3. ****************************************************************
   
4. 
   
5.   1.2005.5.13:ZXJ:  IIc AT24Cxx TEST
   
6. 
   
7. ***************************************************************/
   
8. 
   
9. #include <string.h>
   
10. #include "..\Target\44b.h"
    
11. #include "..\Target\44blib.h"
    
12. #include "..\Target\def.h"
    
13. #include "..\iictest\IIC.h"
    
14. 
    
15. #define WRDATA            (1)
    
16. #define POLLACK     (2)
    
17. #define RDDATA            (3)
    
18. #define SETRDADDR   (4)
    
19. 
    
20. #define IICBUFSIZE 0x20
    
21. 
    
22. U8 _iicData[IICBUFSIZE];
    
23. volatile int _iicDataCount;
    
24. volatile int _iicStatus;
    
25. volatile int _iicMode; //I2C总线读写操作模式
    
26. int _iicPt;
    
27. 
    
28. void __irq IicInt(void);
    
29. 
    
30. void Test_Iic(void)
    
31. {
    
32.     unsigned int i,j,save_F,save_PF;
    
33.     static U8 data[256];
    
34. 
    
35.     Uart_Printf("[IIC Test using AT24Cxx]\n");
    
36. 
    
37.     rINTCON=0x5;
    
38.     rINTMOD=0x0;
    
39.     rINTMSK= BIT_GLOBAL;
    
40.           //rINTMSK=~(BIT_EINT0 | BIT_GLOBAL);
    
41.    
    
42.     save_F=rPCONF;
    
43.     save_PF=rPUPF;
    
44.     rPCONF |=0xa;        //PF0:IICSCL, PF1:IICSDA
    
45.     rPUPF |=0x3;        //pull-up disable
    
46. 
    
47.     pISR_IIC=(unsigned)IicInt;
    
48.     rINTMSK=~(BIT_GLOBAL|BIT_IIC);
    
49.        
    
50.     rIICCON=(1<<7)|(0<<6)|(1<<5)|(0xf);
    
51.     //Enable interrupt, IICCLK=MCLK/16, Enable ACK
    
52.     //40Mhz/16/(15+1) = 257Khz       
    
53.     rIICADD=0x10;   // S3C44B0X slave address
    
54. 
    
55.     rIICSTAT=0x10;
    
56. 
    
57.     Uart_Printf("Write test data into AT24LCxx\n");
    
58. 
    
59.     for(i=0;i<256;i++)
    
60.         Wr24LCxx(0xa0,(U8)i,i);
    
61.     for(i=0;i<256;i++)
    
62.         data[i]=0;
    
63. 
    
64.     Uart_Printf("Read test data from AT24LCxx\n");
    
65.     for(i=0;i<256;i++)
    
66.         Rd24LCxx(0xa0,(U8)i,&(data[i]));
    
67. 
    
68.     for(i=0;i<16;i++)
    
69.     {
    
70.                 for(j=0;j<16;j++)
    
71.                     Uart_Printf("%2x ",data[i*16+j]);
    
72.                 Uart_Printf("\n");
    
73.     }
    
74.    
    
75.     rPCONF=save_F;
    
76.     rPUPF=save_PF;
    
77. }
    
78. 
    
79. 
    
80. void Wr24LCxx(U32 slvAddr,U32 addr,U8 data)
    
81. {
    
82.     _iicMode=WRDATA;
    
83.     _iicPt=0;
    
84.     _iicData[0]=(U8)addr;
    
85.     _iicData[1]=data;
    
86.     _iicDataCount=2;
    
87.    
    
88.     rIICDS=slvAddr;//0xa0
    
89.     rIICSTAT=0xf0; //MasTx,Start
    
90.     //Clearing the pending bit isn't needed because the pending bit has been cleared.
    
91.     while(_iicDataCount!=-1);        //等待数据发送完毕
    
92. 
    
93.     _iicMode=POLLACK;
    
94. 
    
95.     while(1)
    
96.     {
    
97.                 rIICDS=slvAddr;
    
98.                 _iicStatus=0x100;
    
99.                 rIICSTAT=0xf0; //MasTx,Start
    
100.                 rIICCON=0xaf;  //resumes IIC operation.
     
101.                 while(_iicStatus==0x100);
     
102.                 if(!(_iicStatus&0x1))        //
     
103.                     break; // when ACK is received
     
104.     }
     
105.     rIICSTAT=0xd0;  //stop MasTx condition
     
106.     rIICCON=0xaf;   //resumes IIC operation.
     
107.     Delay(1);            //wait until stop condtion is in effect.
     
108. 
     
109.     //write is completed.
     
110. }
     
111.        
     
112. 
     
113. void Rd24LCxx(U32 slvAddr,U32 addr,U8 *data)
     
114. {
     
115.     _iicMode=SETRDADDR;
     
116.     _iicPt=0;
     
117.     _iicData[0]=(U8)addr;
     
118.     _iicDataCount=1;
     
119. 
     
120.     rIICDS=slvAddr;
     
121.     rIICSTAT=0xf0; //MasTx,Start  
     
122.     //Clearing the pending bit isn't needed because the pending bit has been cleared.
     
123.     while(_iicDataCount!=-1);
     
124. 
     
125.     _iicMode=RDDATA;
     
126. 
     
127.     _iicPt=0;
     
128.     _iicDataCount=1;
     
129.    
     
130.     rIICDS=slvAddr;
     
131.     rIICSTAT=0xb0; //MasRx,Start
     
132.     rIICCON=0xaf;  //resumes IIC operation.   
     
133.     while(_iicDataCount!=-1);
     
134. 
     
135.     *data=_iicData[1];
     
136. }
     
137. 
     
138. 
     
139. 
     
140. void __irq IicInt(void)
     
141. {
     
142.     U32 iicSt,i;
     
143.     rI_ISPC=BIT_IIC;
     
144. 
     
145.     iicSt=rIICSTAT;
     
146.     if(iicSt&0x8){} // when bus arbitration is failed.
     
147.     if(iicSt&0x4){} // when a slave address is matched with IICADD
     
148.     if(iicSt&0x2){} // when a slave address is 0000000b
     
149.     if(iicSt&0x1){} // when ACK isn't received
     
150. 
     
151.     switch(_iicMode)
     
152.     {
     
153.         case POLLACK:
     
154.             _iicStatus=iicSt;
     
155.             break;
     
156. 
     
157.         case RDDATA:
     
158.             if((_iicDataCount--)==0)
     
159.             {
     
160.                         _iicData[_iicPt++]=rIICDS;
     
161.                     
     
162.                         rIICSTAT=0x90;  //stop MasRx condition
     
163.                         rIICCON=0xaf;   //resumes IIC operation.
     
164.                         Delay(1);        //wait until stop condtion is in effect.
     
165.                                         //too long time...
     
166.                         //The pending bit will not be set after issuing stop condition.
     
167.                         break;
     
168.             }
     
169.             _iicData[_iicPt++]=rIICDS;
     
170.                                 //The last data has to be read with no ack.
     
171.             if((_iicDataCount)==0)
     
172.                 rIICCON=0x2f;        //resumes IIC operation with NOACK.  
     
173.             else
     
174.                 rIICCON=0xaf;        //resumes IIC operation with ACK
     
175.             break;
     
176. 
     
177.         case WRDATA:
     
178.             if((_iicDataCount--)==0)
     
179.             {
     
180.                         rIICSTAT=0xd0;        //stop MasTx condition
     
181.                         rIICCON=0xaf;        //resumes IIC operation.
     
182.                         Delay(1);        //wait until stop condtion is in effect.
     
183.                         //The pending bit will not be set after issuing stop condition.
     
184.                         break;   
     
185.             }
     
186.             rIICDS=_iicData[_iicPt++];  //_iicData[0] has dummy.
     
187.             for(i=0;i<10;i++);            //for setup time until rising edge of IICSCL
     
188.             rIICCON=0xaf;            //resumes IIC operation.
     
189.             break;
     
190. 
     
191.         case SETRDADDR:
     
192.             //Uart_Printf("[S%d]",_iicDataCount);
     
193.             if((_iicDataCount--)==0)
     
194.             {
     
195.                         break;  //IIC operation is stopped because of IICCON[4]   
     
196.             }
     
197.             rIICDS=_iicData[_iicPt++];
     
198.             for(i=0;i<10;i++);  //for setup time until rising edge of IICSCL
     
199.             rIICCON=0xaf;            //resumes IIC operation.
     
200.             break;
     
201. 
     
202.         default:
     
203.             break;          
     
204.     }
     
205. }
     
206. 
     
207. 
     

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ou513

现在还玩S3C44B0X？

wlh_yuer

ou513 发表于 2017-6-26 10:54
现在还玩S3C44B0X？

没办法，学生