Diff: I2C_read.cpp

Revision:

3:3e8c16b6620c

Child:

4:1c48c9fa44fc

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/I2C_read.cpp	Thu Jun 21 22:11:25 2018 +0000
@@ -0,0 +1,101 @@
+#include "mbed.h"
+
+extern Serial pc;
+extern int frequ = 50; //unit kHz
+extern char dev_addr = 0x00; //fixed
+
+char get_half_byte(int *flag) {
+    char cur_char;
+    cur_char = pc.getc();
+    if ( cur_char >= '0' && cur_char <= '9' ) {
+        cur_char = cur_char - '0';
+        *flag = 1;
+    }
+    else if ( cur_char >= 'a' && cur_char <= 'f') {
+        cur_char = cur_char - 'a'+10;
+        *flag = 1;
+    }
+    else if( cur_char >= 'A' && cur_char <= 'F') {
+        cur_char = cur_char - 'A'+10;
+        *flag = 1;
+    }
+    else *flag = 0; 
+    return cur_char;
+}   
+
+void i2c_read() {
+    char reg_ptr = 0x55;
+    char reg_data = 0x00;
+    char temp;
+    int flag1 = 0;
+    char count = 0;
+    I2C i2c(p9,p10);
+    LPC_PINCON->PINMODE_OD0 = (LPC_PINCON->PINMODE_OD0  | 0x0003); // To make p9 & P10 open_drain
+    pc.printf("\n\n\n \r\tYahoooo! Lets read a Register");
+    //Read the number of Registers
+    while (!flag1) {
+            pc.printf("\n\n\n\r\tEnter the number of registers to read (1 - 16) and hit 'enter' key: ");
+            temp = '0';
+            count = 0;
+            while (temp != '\r') {  //look for enter key
+                count = (count * 10) + (temp - '0');  // converting to number
+                temp = pc.getc();
+                if ((temp < '0' || temp > '9') && temp !='\r') {
+                    pc.printf(" \n\r\t\033[%dm Invalid Chracter!! No worries, let us try again \033[%dm",41,40);
+                    break;
+                }
+            }
+            if (count >= 1 && count <= 16 && temp == '\r') flag1 = 1;
+            else if (temp == '\r') pc.printf(" \n\r\t\033[%dm Invalid Chracter!! No worries, let us try again \033[%dm",41,40);
+    }          
+Re_enter:
+    flag1 = 0;
+    //Read Pointer to the Register that needs to be read
+    while (!flag1) {
+        pc.printf("\n\n \r\tEnter Register Address in hex (0 to f): ");
+        reg_ptr = get_half_byte(&flag1);
+        if (flag1==0) pc.printf(" \033[%dm Invalid Chracter!! No worries, let us try again \033[%dm",41,40);
+    }          
+
+    pc.printf("\n\n\n\r\t\033[%dm", 44);//change backround to blue
+    pc.printf(" Device Address (fixed) = 0x%2.2X ; Register Pointer = 0x%2.2X ; Count = %d ",dev_addr, reg_ptr, count);
+    pc.printf("\033[%dm", 40);//change backround to black
+            
+    pc.printf("\n\n\n \r\tContinue Read? (y/n) [Press 'e' to re-enter Pointer]: ");  
+    temp = 0;
+    while ( temp!='y' && temp!='n' && temp!='e') {
+        temp = pc.getc();
+    }
+    if (temp == 'n') {
+        pc.printf("\n\n \r\tAborting Register Read :(\n\n\r");
+        return;
+    }
+    if (temp == 'e') {
+        pc.printf(" \n\n\n \r\tOk, let us try again :)");
+        goto Re_enter;
+    }
+    i2c.frequency(frequ*1000);
+    i2c.stop(); //add a stop after hot-read
+    wait_us(10);
+    for ( ; (count > 0) && (reg_ptr < 0x10); count = count - 1) {
+        i2c.start();
+        flag1 = i2c.write(dev_addr); 
+        if (flag1 != 1) pc.printf("\n\n\n \r\tNo Ack for dev addr :(");
+        flag1 = i2c.write(reg_ptr);
+        if (flag1 != 1) pc.printf("\n\n \r\tNo Ack reg pointer :(");
+        i2c.stop();
+        wait_us(10);
+        i2c.start();
+        flag1 = i2c.write(dev_addr | 0x01); //lsb 1 for read
+        if (flag1 != 1) pc.printf("\n\n \r\tNo Ack for dev addr :(");         
+        reg_data = i2c.read(0); //0- donot send ack after read is done         
+        pc.printf("\n\n\n \r\tRead 0x%2.2X = 0x%2.2X ", reg_ptr, reg_data);
+        wait_us(5);
+        i2c.stop();      
+        if (reg_data == 0xff) pc.printf("  |\033[%dm  Register read might not be sucessfull \033[%dm ",45,40);
+        reg_ptr = reg_ptr + 1;
+        wait_us(120);        
+    }
+    pc.printf("\n\n\n \r\tYeahhh! Register Read Complete\n\n\r");
+    i2c.~I2C();   
+}  
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