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https://github.com/markqvist/OpenModem.git
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60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
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#include "hardware.h"
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#include <net/afsk.h>
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#include <cpu/irq.h>
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#include <avr/io.h>
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#include <avr/interrupt.h>
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static Afsk *ctx;
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void hw_afsk_adcInit(int ch, Afsk *_ctx)
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{
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ctx = _ctx;
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ASSERT(ch <= 5);
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AFSK_STROBE_INIT();
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AFSK_STROBE_OFF();
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/* Set prescaler to clk/8 (2 MHz), CTC, top = ICR1 */
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TCCR1A = 0;
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TCCR1B = BV(CS11) | BV(WGM13) | BV(WGM12);
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/* Set max value to obtain a 9600Hz freq */
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ICR1 = ((CPU_FREQ / 8) / 9600) - 1;
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/* Set reference to AVCC (5V), select CH */
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ADMUX = BV(REFS0) | ch;
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DDRC &= ~BV(ch);
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PORTC &= ~BV(ch);
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DIDR0 |= BV(ch);
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/* Set autotrigger on Timer1 Input capture flag */
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ADCSRB = BV(ADTS2) | BV(ADTS1) | BV(ADTS0);
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/* Enable ADC, autotrigger, 1MHz, IRQ enabled */
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/* We are using the ADC a bit out of specifications otherwise it's not fast enough for our
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* purposes */
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ADCSRA = BV(ADEN) | // ADC Enable
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BV(ADSC) | // ADC Start converting
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BV(ADATE) | // Enable autotriggering
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BV(ADIE) | // ADC Interrupt enable
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BV(ADPS2); // Enable prescaler flag 2 (1-0-0 = division by 16 = 1MHz)
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}
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bool hw_afsk_dac_isr;
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/*
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* This is how you declare an ISR.
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*/
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DECLARE_ISR(ADC_vect)
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{
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TIFR1 = BV(ICF1);
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afsk_adc_isr(ctx, ((int16_t)((ADC) >> 2) - 128));
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if (hw_afsk_dac_isr)
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PORTD = afsk_dac_isr(ctx) & 0xF0;
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else
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PORTD = 128;
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}
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