kopia lustrzana https://github.com/fsphil/hadie
Interrupt driven RTTY
rodzic
3d9b7b7d7d
commit
d841092e74
2
hadie.c
2
hadie.c
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@ -35,7 +35,7 @@ int main(void)
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while(1)
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{
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rtx_string("Hello, World!\n");
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}
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return(0);
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78
rtty.c
78
rtty.c
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@ -10,76 +10,82 @@
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#include "config.h"
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#include <avr/io.h>
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#include <util/delay.h>
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#include <avr/interrupt.h>
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#include <avr/pgmspace.h>
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#define RTTY_DELAY (1000000 / RTTY_BAUD)
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#include <string.h>
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#include "rtty.h"
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/* MARK = Upper tone, Idle, bit */
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#define TXENABLE (0x04)
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#define MARK (0x02)
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#define SPACE (0x01)
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/* RTTY speed */
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uint16_t rtty_delay = (1000000 / RTTY_BAUD);
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//#define RTTY_DELAY rtty_delay
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#define TXBIT(b) PORTB = (PORTB & ~(MARK | SPACE)) | (b)
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void rtx_baud(int baud)
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{
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rtty_delay = 1000000 / baud;
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}
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volatile uint8_t *txbuf = 0;
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volatile uint16_t txlen = 0;
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inline void rtx_bit(uint8_t b)
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ISR(TIMER0_COMPA_vect)
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{
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PORTB = (PORTB & ~(MARK | SPACE)) | b;
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}
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void rtx_byte(uint8_t byte)
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{
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int i;
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/* The currently transmitting byte, including framing */
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static uint8_t byte = 0x00;
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static uint8_t bit = 0x00;
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/* Start bit */
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rtx_bit(SPACE);
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_delay_us(RTTY_DELAY);
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/* 7 bit */
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for(i = 0; i < 8; i++)
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uint8_t b = 0;
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switch(bit++)
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{
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if(byte & 1 << i) rtx_bit(MARK); else rtx_bit(SPACE);
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_delay_us(RTTY_DELAY);
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case 0: b = 0; break; /* Start bit */
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case 9: b = 1; break; /* Stop bit */
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case 10: b = 1; TCNT0 += OCR0A >> 1; bit = 0; break; /* Stop bit 0.5 */
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default: b = byte & 1; byte >>= 1; break;
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}
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/* Stop bit 1 */
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rtx_bit(MARK);
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_delay_us(RTTY_DELAY);
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_delay_us(RTTY_DELAY / 2);
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TXBIT(b ? MARK : SPACE);
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if(bit == 0 && txlen > 0)
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{
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byte = *(txbuf++);
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txlen--;
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}
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}
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void rtx_string(char *s)
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{
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while(*s != '\0') rtx_byte(*(s++));
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uint16_t length = strlen(s);
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rtx_wait();
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txbuf = (uint8_t *) s;
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txlen = length;
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}
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void rtx_string_P(PGM_P s)
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{
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char b;
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while((b = pgm_read_byte(s++)) != '\0') rtx_byte(b);
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//char b;
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//while((b = pgm_read_byte(s++)) != '\0') rtx_byte(b);
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}
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void rtx_data(uint8_t *data, size_t length)
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{
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int b;
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for(b = 0; b < length; b++) rtx_byte(data[b]);
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rtx_wait();
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txbuf = data;
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txlen = length;
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}
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void rtx_wait()
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{
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/* TODO: Wait for interrupt driven TX to finish */
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/* Wait for interrupt driven TX to finish */
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while(txlen > 0);
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}
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void rtx_init()
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{
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/* We use Port B pins 1, 2 and 3 - MARK by default */
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rtx_bit(MARK);
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/* RTTY is driven by TIMER0 in CTC mode */
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TCCR0A = _BV(WGM01); /* Mode 2, CTC */
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TCCR0B = _BV(CS02) | _BV(CS00); /* prescaler 1024 */
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OCR0A = F_CPU / 1024 / RTTY_BAUD;
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TIMSK0 = _BV(OCIE0A); /* Enable interrupt */
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/* We use Port B pins 1, 2 and 3 */
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TXBIT(MARK);
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PORTB |= TXENABLE;
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DDRB |= MARK | SPACE | TXENABLE;
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}
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1
rtty.h
1
rtty.h
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@ -13,7 +13,6 @@
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#include <stdint.h>
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#include <avr/pgmspace.h>
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extern void rtx_baud(int baud);
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extern void rtx_string(char *s);
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extern void rtx_string_P(PGM_P s);
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extern void rtx_data(uint8_t *data, size_t length);
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