main.cpp

00001 #include "mbed.h"
00002 
00003 #define EE_READ  0x400   // 10 XXXXXXXXX(A8-A0)
00004 #define EE_WRITE 0x200   // 01 XXXXXXXXX(A8-A0)
00005 #define EE_EWEN  0x1FF   // 00 11XXXXXXX(X is DONT CARE)
00006 #define EE_EWDS  0x000   // 00 00XXXXXXX(X is DONT CARE)
00007 #define EE_ERASE 0x600   // 11 XXXXXXXXX(A8-A0)
00008 
00009 Serial device(PA_9, PA_10);  // tx, rx
00010 DigitalOut CS(PC_0);
00011 DigitalOut CK(PB_13);
00012 DigitalIn  DI(PB_14);
00013 DigitalOut DO(PB_15);
00014 
00015 void vSend(unsigned short usCommand)
00016 {
00017     signed char i=10;
00018     DO=1;        //SB
00019     CS=1;        // Chip Select High
00020     wait_us(1);  // SB Clock Generation
00021     CK=1;
00022     wait_us(1);
00023     CK=0;
00024     while(i>=0)
00025     {
00026         DO = (usCommand>>i)&0x01;
00027         i--;
00028         wait_us(1);
00029         CK=1;
00030         wait_us(1);
00031         CK=0;
00032     }
00033 }
00034 void vWriteEnable()
00035 {
00036     vSend(EE_EWEN);
00037     wait_us(1);
00038     CS=0;  //Chip Select Low
00039 }
00040 void vWriteDisable()
00041 {
00042     vSend(EE_EWDS);
00043     wait_us(1);
00044     CS=0;  //Chip Select Low
00045 }
00046 void vErase(unsigned short usAddr)
00047 {
00048     vSend(EE_ERASE|usAddr);
00049     wait_us(1);
00050     CS=0;
00051 /** wait busy flag clear */
00052     wait_us(1);     // tcs > 250ns @2.7V
00053     CS=1;
00054     wait_us(1);     // tsv < 250ns @2.7V
00055     while(DI==0); // 0.1ms < twp < 10ms 
00056     CS=0;
00057 }
00058 void vWrite(unsigned short usAddr, unsigned char ucData)
00059 {
00060     signed char i=7;
00061     vSend(EE_WRITE|usAddr);
00062     for(i=7;i>=0;i--)
00063     {
00064         DO = (int)( (ucData>>i)&0x0001 );
00065         wait_us(1);
00066         CK=1;
00067         wait_us(1);
00068         CK=0;
00069     }
00070     CS=0;
00071 /** wait busy flag clear */
00072     wait_us(1);     // tcs > 250ns @2.7V
00073     CS=1;
00074     wait_us(1);     // tsv < 250ns @2.7V
00075     while(DI==0); // 0.1ms < twp < 10ms 
00076     CS=0;
00077 }
00078 unsigned char ucRead(unsigned short usAddr)
00079 {
00080     unsigned char data=0;
00081     signed char i=7;
00082     
00083     vSend(EE_READ|usAddr);
00084     wait_us(1);
00085     
00086     for(i=7;i>=0;i--)
00087     {
00088         CK=1;
00089         wait_us(1);
00090         CK=0;
00091         data = data | (DI<<i);
00092         wait_us(1);
00093     }
00094     CS=0;
00095     
00096     return data;
00097 }
00098 int main()
00099 {
00100     unsigned char ucI=0;
00101     
00102     CS = 0;  //default state for Chip Select and Clock
00103     CK = 0;
00104     
00105     device.baud(19200);
00106     device.printf("The Program demostrating the IC AT93C56 EEPROM \r\n");
00107 
00108     device.printf("Going to Write Enable \r\n");    
00109     vWriteEnable();
00110 
00111     device.printf("Going to Erase Addr 0 \r\n");    
00112     vErase(0);
00113     device.printf("Going to Write Value AA to Addr 0 \r\n");    
00114     vWrite(0,0xAA);
00115     device.printf("Read Back Value %04X\r\n,",ucRead(0));
00116     
00117     device.printf("Going to Erase Addr 1 \r\n");    
00118     vErase(1);      
00119     device.printf("Going to Write Value BB to Addr 1 \r\n");    
00120     vWrite(1,0xBB);
00121     device.printf("Read Back Value %04X\r\n,",ucRead(1));
00122 
00123     device.printf("Going to Erase Addr 2 \r\n");    
00124     vErase(2);      
00125     device.printf("Going to Write Value CC to Addr 2 \r\n");    
00126     vWrite(2,0xCC);
00127     device.printf("Read Back Value %04X\r\n,",ucRead(2));
00128     
00129     device.printf("Going to Write Disable \r\n");   
00130     
00131     vWriteDisable();    
00132     
00133     while(1)
00134     {
00135         for(ucI=0;ucI<64;ucI++)
00136         {
00137             device.printf("%04X   ==============   %d\r\n,",ucRead(ucI),ucI);
00138             wait(0.5);
00139         }
00140     }
00141 }