Samsung S3C84E5 user manual Internal A/D Conversion Procedure, 15-5

S3C84E5/C84E9/P84E9 A/D CONVERTER

INTERNAL A/D CONVERSION PROCEDURE

1.Analog input must remain between the voltage range of AVSS and AVREF.

2.Configure P3.0–P3.7 for analog input before A/D conversions. To do this, you load the appropriate value to the P3CONH and P3CONL (for ADC0–ADC7) registers.

3.Before the conversion operation starts, you must first select one of the eight input pins (ADC0–ADC7) by writing the appropriate value to the ADCON register.

4.When conversion has been completed, (50 clocks have elapsed), the EOC, ADCON.3 flag is set to "1", so that a check can be made to verify that the conversion was successful.

5.The converted digital value is loaded to the output register, ADDATAH (8-bit) and ADDATAL (2-bit), then the ADC module enters an idle state.

6.The digital conversion result can now be read from the ADDATAH and ADDATAL register.

	VDD
Reference	104	R	AVref
Voltage
Input
	VDD
Analog			ADC0-ADC7
Input Pin
		101	S3C84E5/
			S3C84E9/
			S3P84E9
			AVss
			Vss

NOTE: The symbol "R" signifies an offset resistor with a value of from 50 to 100Ω .

Figure 15-5. Recommended A/D Converter Circuit for Highest Absolute Accuracy

15-5