37 lines
1.1 KiB
C
37 lines
1.1 KiB
C
/*
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This example showcases digital input and output using the AVR chip's GPIO
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pins. For all pins, we first have to configure them as either input or output.
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We do this by writing to the DDRx register (data direction register) either a 1
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(for output) or 0 (for input).
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We can set the output of a pin by writing to PORTx, using bitwise operators.
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Reading can be done by reading from PINx, using bitwise operators.
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*/
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#include <avr/io.h>
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#include <util/delay.h>
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int main() {
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// Pin 12 == Port B4, aka 4th bit on the B register.
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// Set pin 12 as output.
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DDRB |= 1 << PORTB4;
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// Set pin 5 as input.
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DDRD &= ~(1 << PORTD5);
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// Write a 0 to pin 12 initially.
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PORTB &= ~(1 << PORTB4);
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uint8_t led = 0;
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while (1) {
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// Write current led status to pin 12.
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if (led) {
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PORTB |= 1 << PORTB4;
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} else {
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PORTB &= ~(1 << PORTB4);
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}
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led = !led;
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_delay_ms(1000.0);
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// Read input from pin 5. If it's HIGH, keep the LED on.
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uint8_t pin5Value = (PIND & (1 << PIND5)) >> PIND5;
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if (pin5Value) led = 1;
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}
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return 0;
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} |