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54 lines
1.2 KiB
54 lines
1.2 KiB
9 years ago
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#include <avr/io.h> // register definitions
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#include <avr/pgmspace.h> // storing data in program memory
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#include <avr/interrupt.h> // interrupt vectors
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#include <util/delay.h> // delay functions
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#include <stdint.h> // C header for int types like uint8_t
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#include <stdbool.h> // C header for the bool type
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// Include stuff from the library
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#include "lib/iopins.h"
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#include "lib/usart.h"
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void main() __attribute__ ((noreturn));
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// Pins
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#define LED 13
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// UART receive handler
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ISR(USART_RX_vect)
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{
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uint8_t b = usart_rx();
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usart_tx(b); // send back
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}
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void main()
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{
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usart_init(8); // set usart @ 115200 (8 is a UBRR value)
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usart_rx_isr_enable(true); // enable RX interrupt handler
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// configure pins
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as_output(LED);
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// globally enable interrupts (for the USART_RX handler)
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sei();
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while (1) {
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// This string is in the program memory
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// PSTR is a special macro that puts it there.
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// That means it does not waste ram space, but
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// needs special treatment when being read.
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// (avr-gcc is a bit dumb in this)
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usart_puts_P( PSTR("Hello World\r\n") ); // Print a string to USART
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// This one is copied to RAM before being printed = bad.
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usart_puts("Wastin' RAM!\r\n");
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pin_toggle(13);
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_delay_ms(500);
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}
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}
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