8-CHANNEL ADC(ANALOG MUX) interfacing with parallel port
This tutorial is taken from the book MY EXPERIENCE IN PARALLEL PORT INTERFACING. you can download it free from the files section(file:-parallelport(3 files) of yahoo group-booksbybibin http://groups.yahoo.com/group/booksbybibin/ comments about this book on www.booksbybibin.blogspot.com 8-CHANNEL ADC(USING ANALOG MUX) Figure shows analog mux is used to multiplex 8 analog voltages to the ADC. Here we are using an analog mux MC14051 or CD4051. The selection pins of the analog mux is connected to the output of the control port.INH is disabled. Thus by selecting proper inputs we can get different channel outputs. Analog mux can work as a digital mux while digital mux can't. #include"bparlib.c" float Read_adc(void); void main() { clrscr(); //selecting 0 the value Clear_ControlPort_bit(1); Clear_ControlPort_bit(2); Clear_ControlPort_bit(3); printf("\nvalue of ADMUX 0 is %f",Read_adc()); //selecting channel-1 the value Set_ControlPort_bit(1); Clear_ControlPort_bit(2); Clear_ControlPort_bit(3); printf("\nvalue of ADMUX 1 is %f",Read_adc()); //selecting channel-2 the value Clear_ControlPort_bit(1); Set_ControlPort_bit(2); Clear_ControlPort_bit(3); printf("\nvalue of ADMUX 2 is %f",Read_adc()); //selecting channel-3 the value Set_ControlPort_bit(1); Set_ControlPort_bit(2); Clear_ControlPort_bit(3); printf("\nvalue of ADMUX 3 is %f",Read_adc()); //selecting channel-4 the value Clear_ControlPort_bit(1); Clear_ControlPort_bit(2); Set_ControlPort_bit(3); printf("\nvalue of ADMUX 4 is %f",Read_adc()); //selecting channel-5 the value Set_ControlPort_bit(1); Clear_ControlPort_bit(2); Set_ControlPort_bit(3); printf("\nvalue of ADMUX 5 is %f",Read_adc()); //selecting channel-6 the value Clear_ControlPort_bit(1); Set_ControlPort_bit(2); Set_ControlPort_bit(3); printf("\nvalue of ADMUX 6 is %f",Read_adc()); //selecting channel-7 the value Set_ControlPort_bit(1); Set_ControlPort_bit(2); Set_ControlPort_bit(3); printf("\nvalue of ADMUX 7 is %f",Read_adc()); getch(); } float Read_adc(void) { float b; delay(1); Clear_ControlPort_bit(0); delay(1); Set_ControlPort_bit(0); delay(1); b=Read_DataPort(); b=b*5/255; return(b); }