| 1 | #define F_CPU 1000000UL // Sets up the default speed for delay.h |
| 2 | // this is the header file that tells the compiler what pins and ports, etc. |
| 3 | // are available on this chip. |
| 4 | #include <avr/io.h> |
| 5 | |
| 6 | // define what pins the LEDs are connected to. |
| 7 | // in reality, PD6 is really just '6' |
| 8 | #define LED PD5 |
| 9 | |
| 10 | // Some macros that make the code more readable |
| 11 | #define output_low(port,pin) port &= ~(1<<pin) |
| 12 | #define output_high(port,pin) port |= (1<<pin) |
| 13 | #define set_input(portdir,pin) portdir &= ~(1<<pin) |
| 14 | #define set_output(portdir,pin) portdir |= (1<<pin) |
| 15 | |
| 16 | // this is just a program that 'kills time' in a calibrated method |
| 17 | void delay_ms(uint8_t ms) { |
| 18 | uint16_t delay_count = F_CPU / 17500; |
| 19 | volatile uint16_t i; |
| 20 | |
| 21 | while (ms != 0) { |
| 22 | for (i=0; i != delay_count; i++); |
| 23 | ms--; |
| 24 | } |
| 25 | } |
| 26 | |
| 27 | int main(void) { |
| 28 | // initialize the direction of PORTD #6 to be an output |
| 29 | set_output(DDRD, LED); |
| 30 | |
| 31 | while (1) { |
| 32 | // turn on the LED for 200ms |
| 33 | output_high(PORTD, LED); |
| 34 | delay_ms(200); |
| 35 | // now turn off the LED for another 200ms |
| 36 | output_low(PORTD, LED); |
| 37 | delay_ms(200); |
| 38 | // now start over |
| 39 | } |
| 40 | } |