ADC_setup.cpp

00001 // ADC_setup.cpp
00002 
00003 #include "header.h"
00004 /*****************************************************
00005  variables and defines
00006  ****************************************************/
00007 
00008 int ADC_channel=1;     // ADC channel 1
00009 
00010 /*****************************************************
00011   subroutines
00012 *****************************************************/
00013 void ADC_init(){
00014 
00015      PINSEL1=0x00010000;  //set AD0.1 pin to 0000 0000 0000 0001 0000 0000 0000 0000 = ADC
00016      PCONP |= (1 << 12);  // enable ADC clock 
00017      AD0CR = (1 << ADC_channel)     // channel 1 
00018            | (4 << 8)     // This gives us 3MHz 
00019            | (0 << 16)    // BURST = 0, software control  
00020            | (0 << 17)    // CLKS = 0 (11-bits)  
00021            | (1 << 21)    // PDN = 1  
00022            | (0 << 22)    // TEST1:0 = 00  
00023            | (1 << 24)    // START = 1 start A/D conversion 
00024            | (0 << 27);   // EDGE = 0 (CAP/MAT singal falling,trigger A/D conversion) 
00025 }
00026 float ADC_read() { 
00027 
00028     int data;
00029      
00030     // start A/D conversion on channel 
00031     AD0CR &= (AD0CR & 0xFFFFFF00);  
00032     AD0CR |= (1 << ADC_channel) | (1 << 24);       
00033   
00034     delay_l();
00035   
00036     // wait for it to finish by polling the ADC DONE bit         
00037     while((AD0GDR & 0x80000000) == 0) 
00038     {
00039     }
00040       
00041     // get the data and stop the adc 
00042     data = AD0GDR; 
00043     AD0CR &= 0xF8FFFFFF; 
00044   
00045     // shift data and mask to give 8-bit ADC value
00046     data=(data>>8)&0x00000FF;  
00047     return data; 
00048  }