main.cpp

00001 #include "mbed.h"
00002  
00003 #define MCP24AA02_ADDR     (0xA0) // 24AA02 2K EEPROM using i2c Address
00004                                   // for the 22AA025 variant this can be 0xA0,0xA2,0xA4,0xA6,0xA8,0xAA,0xAC,0xAE
00005                                   // since LSB is used to to control a WRITE(0) or a READ(1) Operation
00006 #define WRITE              (0x00) // 24AA02 2K EEPROM using i2c Write bit
00007 #define READ               (0x01) // 24AA02 2K EEPROM using i2c Read bit
00008 #define MCP24AA02_MID      (0xFA) // Manufacturer ID Address (Read Only 0x29==Microchip)
00009 #define MCP24AA02_DID      (0xFB) // Device ID Adress (Read Only 0x41==4 is i2c family and 1 is 2K device)
00010                                   // Information from Microchip Datasheet DS20005202A Part #24AA02UID/24AA025UID
00011 /* This is a very simple program to demonstrate the ease of use of the i2c bus utilising an EEPROM.
00012    Do not forget that Pull Up resistors are required on the SDA and SCL lines
00013    (Typically 2K ohms for 400KHz bus speeds)
00014    These are required since devices connected with the i2c will have 'open drain' (or open collector)
00015    circuitry to allow wire 'ORing' of their respective connections
00016    Used with a stm32-Nucleo-F401RE
00017 */
00018 
00019 I2C i2c(I2C_SDA, I2C_SCL); //I2C Class Pin Assignments see I2C.h
00020  
00021 Serial pc(SERIAL_TX, SERIAL_RX); //Serial Class Pin Assignments see Serial.h
00022 
00023 void readID(int addy)
00024 {
00025     char ucdata_write[1];
00026     char ucdata_read[1];
00027     ucdata_write[0] = addy; //MCP24AA02_DID, Address here for Device ID
00028     
00029     while (i2c.write((MCP24AA02_ADDR|WRITE), ucdata_write, 1, 0)){} //Wait for ACK if EEPROM is in 'write' cycle
00030     
00031     {
00032         i2c.read((MCP24AA02_ADDR|READ),ucdata_read,1,0);
00033         if (ucdata_read[0]==0x29)
00034         {
00035             pc.printf("Code=%#x (Microchip Technology ltd.(c))\n\r",ucdata_read[0]);return;
00036         }
00037         if (ucdata_read[0]==0x41)
00038         {
00039             pc.printf("Code=%#x (2K EEPROM Using i2c)\n\r",ucdata_read[0]);
00040         }
00041         else
00042         {
00043             pc.printf("0x%x 0x%X %c\n\r",addy,ucdata_read[0],(ucdata_read[0]));
00044         }    
00045      }
00046 }
00047 
00048 void readEE(int addy)
00049 {
00050     char ucdata_write[1];
00051     char ucdata_read[1];
00052     ucdata_write[0] = addy; //Address here to read
00053     while (i2c.write((MCP24AA02_ADDR|WRITE), ucdata_write, 1, 0)){} //Wait for ACK if EEPROM is in 'write' cycle
00054     i2c.read((MCP24AA02_ADDR|READ),ucdata_read,1,0); //Note 'OR' Address with Read bit
00055     pc.printf("%#X %c",ucdata_read[0],ucdata_read[0]);
00056  }
00057 
00058 void writeEE(int addy,int data)
00059 {
00060     char ucdata_write[2];
00061     ucdata_write[0] = addy;
00062     ucdata_write[1] = data;
00063     while (i2c.write((MCP24AA02_ADDR|WRITE), ucdata_write, 1, 0)){} //Wait for ACK if EEPROM is in 'write' cycle
00064     i2c.write((MCP24AA02_ADDR|WRITE),ucdata_write,2,0); //Note 'OR' Adress with Write bit
00065     pc.printf("%04d %c\t",addy,data);
00066 }
00067 
00068 void eraseEE(void)
00069 {
00070     for (int i=0;i<0xFA;i++) //0xFA to 0xFF are read only with Manufacture/Hardware ID and a Unique Serial Number
00071     {
00072         writeEE(i,0xFF);
00073     }
00074 }
00075 
00076 int main()
00077 {
00078     unsigned int uibaudrate=115200;
00079     pc.baud(uibaudrate);
00080     
00081     unsigned int uifrequency=400000; //400KHz for i2c Max
00082     i2c.frequency (uifrequency);
00083 
00084     char ucdata_write[1];    
00085     if (!i2c.write((MCP24AA02_ADDR|WRITE), ucdata_write, 1, 0))// Check for ACK from EPPROM
00086     {
00087         pc.printf("\n\rHello World ");
00088         pc.printf("at %u BAUD and %uKHz i2c Frequency\n\r",uibaudrate,uifrequency/1000);
00089         pc.printf("Using mbed.org Martin\n\r");
00090         readID(MCP24AA02_MID);
00091         readID(MCP24AA02_DID);
00092         //  Uncomment the following 6 lines of code to write Data into the EEPROM
00093         /*
00094         writeEE(0x00,0x4D); // ASCII M
00095         writeEE(0x01,0x61); // ASCII a
00096         writeEE(0x02,0x72); // ASCII r
00097         writeEE(0x03,0x74); // ASCII t
00098         writeEE(0x04,0x69); // ASCII i
00099         writeEE(0x05,0x6E); // ASCII n
00100         pc.printf("\n\r");
00101         */
00102 
00103         //Uncomment the following line to Erase the EEPROM
00104         // eraseEE();
00105     
00106         for (int i=0;i<=0x5;i++) //Just going to read the first 6 (zero to five) locations in the EEPROM
00107         {
00108             readEE(i);pc.printf("\t");          //A Bit of formating going to tab into 8 columns
00109             if (!((i+1)%8)){pc.printf("\n\r");} //of data
00110         }
00111     }
00112     else
00113     {
00114         pc.printf("\n\rCannot get an ACK from the Device check connections!\n\r");
00115     }
00116 }
00117