//-----------------------------------------------------------------------------
// 這部分程序是利用040內部溫度傳感器采集出溫度值及電壓的值,然后通過
//以太網將這些值發送出去的.
//-----------------------------------------------------------------------------
#include <string.h>

#include "C8051f040.h"
#include "net.h"
#include "analog.h"

extern char xdata text[];
UINT idata cpu_temperature, air_temperature, cpu_voltage;
UCHAR idata mux_select;

sfr16 ADC0     = 0xbe;                

//--------------------------------------------------------------------------
// 初始化ADC
//--------------------------------------------------------------------------
void init_adc(void)
{
   char SFRPAGE_SAVE=SFRPAGE;
   SFRPAGE = ADC0_PAGE;
	ADC0CN = 0x81;                     
	REF0CN = 0x07;                     
                                       	
   mux_select = MUX_CPU_TEMP;	  		
   AMX0SL = MUX_CPU_TEMP; 	
   ADC0CF = (SYSCLK/2500000) << 3;    
   EIE2 &= ~0x02;                      
   EIE1 &= ~0x04;                      
   SFRPAGE = SFRPAGE_SAVE;
}



//--------------------------------------------------------------------------
// This function is a little state machine which reads one analog
// inputs at a time, out of the 3 possible inputs
//  1. On-chip temperature      片內溫度
//  2. External air temperature
//  3. CPU operating voltage	CPu的工作電壓
//--------------------------------------------------------------------------
void read_analog_inputs(void)
{
   	 ULONG idata temp_long;
     char SFRPAGE_SAVE = SFRPAGE;
	 SFRPAGE = ADC0_PAGE;
     AD0INT = 0;                      
     AD0BUSY = 1;                     
     while (AD0INT == 0);             
	switch (mux_select)
	   {
		case MUX_CPU_TEMP:
	      	temp_long = ADC0*2 - 42380;
		    temp_long= (temp_long * 100L) / 156;
			cpu_temperature=temp_long;
			AMX0SL = MUX_CPU_VOLTS;		
			mux_select = MUX_CPU_VOLTS;
		break;

		case MUX_CPU_VOLTS:
			temp_long = ADC0;
			temp_long = 24*temp_long/655;
			cpu_voltage = temp_long;
			AMX0SL = MUX_AIR_TEMP;		
			mux_select = MUX_AIR_TEMP;
		break;

		case MUX_AIR_TEMP:
			temp_long = ADC0;
			temp_long = 24*temp_long/655;
			air_temperature = temp_long;
			AMX0SL = MUX_CPU_TEMP;	 
			mux_select = MUX_CPU_TEMP;
		break;

		default:
			AMX0SL = MUX_CPU_TEMP;
			mux_select = MUX_CPU_TEMP;
		break;
  	    }
    	SFRPAGE = SFRPAGE_SAVE;
}