#include
#include
#include

// define P1.0 to check STATUS.
sbit STATUS = P1^0;

unsigned char xdata CTRL? _at_ 0x2FFF;
unsigned char xdata ADSEL _at_ 0x4FFF;
unsigned char hByte;
unsigned char lByte;

void adc_Convert (void)
?{ // Start a conversion with A0 and A/$C$ low.
?? // The convesion takes place on rising CE edge.
?? CTRL? = 0x00;
?? ADSEL = 0x00;
?? // Wait until we have completed a conversion .
?? while(STATUS==1);
?? // Set R/$C$ with A0 low and read the low byte.
?? CTRL? = 0x02;
?? hByte = ADSEL;
?? // Set R/$C$ with A0 high and read the high.
?? CTRL? = 0x03;
?? lByte = ADSEL;
?}

void main(void)
?{ unsigned int delay, MSB , LSB, adc_Res;
?? // Initialize serial interface
?? SCON? = 0xDA;??????? // SCON: mode 1, 8-bit UART, enable rcvr????? */
?? TMOD |= 0x20;??????? // TMOD: timer 1, mode 2, 8-bit reload??????? */
?? TH1?? = 0xFD;???????? // TH1:? reload value for 1200 baud @ 12MHz?? */
?? TR1?? = 1;?????????? // TR1:? timer 1 run????????????????????????? */
?? TI??? = 1;?????????? // TI:?? set TI to send first char of UART??? */
??
?? while(1)
??? { adc_Convert();
????? MSB=(unsigned int)(hByte << 4);
????? LSB=(unsigned int)(lByte >> 4);
????? // adc_Res now has the converted data with 12-bit resolution.
????? adc_Res = MSB + LSB;
????? // Send adc results to the serial interface
????? printf("ADC READINGS: %03Xh\n", adc_Res);
???? // simple delay - it is mcu clock dependent !
????? for (delay=0; delay<10000; delay++)
?????? ;
??? }
?}