Description
To learn how to program the ATmega Analog to Digital Converters by initializing and using the appropriate special function registers. You will develop two functions, adc_init, and adc_read, and a program which uses the two functions to read analog data from a photoresistor and sends the data over serial to a PC.
Procedure:
- Read chapter 8 of the textbook and browse section 26 of the Atmel 2560’s datasheet, paying extra attention to sections 26.2, 26.3, 26.4, and 26.8.
- Write two ANSI C functions:
- void adc_init( ) – Initializes the Analog to Digital Converter to be ready to read analog data.
- unsigned int adc_read(unsigned char adc_channel) – Returns the analog data read from the analog channel given as a parameter.
- Connect a photoresistor and an axial resistor in series as a voltage divider and write a program which reads the analog voltage of the divider and sends the voltage values over serial to your PC. Use the Arduino IDE’s Serial Plotter to plot the voltage values.
- Modify the program to turn on the on-board LED when the light level is above some threshold. Notes:
