/*------------------------------------------------------------------*/
/* --- STC MCU Limited ---------------------------------------------*/
/* --- STC12C5Axx Series MCU A/D Conversion Demo -------------------*/
/* --- Mobile: (86)13922805190 -------------------------------------*/
/* --- Fax: 86-755-82905966 ----------------------------------------*/
/* --- Tel: 86-755-82948412 ----------------------------------------*/
/* --- Web: www.STCMCU.com -----------------------------------------*/
/* If you want to use the program or the program referenced in the */
/* article, please specify in which data and procedures from STC */
/*------------------------------------------------------------------*/
#include "reg51.h"
#include "intrins.h"
#define FOSC 18432000L
#define BAUD 9600
typedef unsigned char BYTE;
typedef unsigned int WORD;
/*Declare SFR associated with the ADC */
sfr ADC_CONTR = 0xBC; //ADC control register
sfr ADC_RES = 0xBD; //ADC hight 8-bit result register
sfr ADC_LOW2 = 0xBE; //ADC low 2-bit result register
sfr P1ASF = 0x9D; //P1 secondary function control register
/*Define ADC operation const for ADC_CONTR*/
#define ADC_POWER 0x80 //ADC power control bit
#define ADC_FLAG 0x10 //ADC complete flag
#define ADC_START 0x08 //ADC start control bit
#define ADC_SPEEDLL 0x00 //420 clocks
#define ADC_SPEEDL 0x20 //280 clocks
#define ADC_SPEEDH 0x40 //140 clocks
#define ADC_SPEEDHH 0x60 //70 clocks
void InitUart();
void SendData(BYTE dat);
void Delay(WORD n);
void InitADC();
BYTE ch = 0; //ADC channel NO.
void main()
{
InitUart(); //Init UART, use to show ADC result
InitADC(); //Init ADC sfr
IE = 0xa0; //Enable ADC interrupt and Open master interrupt switch
//Start A/D conversion
while (1);
}
/*----------------------------
ADC interrupt service routine
----------------------------*/
void adc_isr() interrupt 5 using 1
{
ADC_CONTR &= !ADC_FLAG; //Clear ADC interrupt flag
SendData(ch); //Show Channel NO.
SendData(ADC_RES); //Get ADC high 8-bit result and Send to UART
//if you want show 10-bit result, uncomment next line
// SendData(ADC_LOW2); //Show ADC low 2-bit result
if (++ch > 7) ch = 0; //switch to next channel
ADC_CONTR = ADC_POWER | ADC_SPEEDLL | ADC_START | ch;
}
/*----------------------------
Initial ADC sfr
----------------------------*/
void InitADC()
{
P1ASF = 0xff; //Set all P1 as analog input port
ADC_RES = 0; //Clear previous result
ADC_CONTR = ADC_POWER | ADC_SPEEDLL | ADC_START | ch;
Delay(2); //ADC power-on delay and Start A/D conversion
}
/*----------------------------
Initial UART
----------------------------*/
void InitUart()
{
SCON = 0x5a; //8 bit data ,no parity bit
TMOD = 0x20; //T1 as 8-bit auto reload
TH1 = TL1 = -(FOSC/12/32/BAUD); //Set Uart baudrate
TR1 = 1; //T1 start running
}
/*----------------------------
Send one byte data to PC
Input: dat (UART data)
Output:-
----------------------------*/
void SendData(BYTE dat)
{
while (!TI); //Wait for the previous data is sent
TI = 0; //Clear TI flag
SBUF = dat; //Send current data
}
/*----------------------------
Software delay function
----------------------------*/
void Delay(WORD n)
{
WORD x;
while (n--)
{
x = 5000;
while (x--);
}
}