Working

Modem/hardware.c

@@ -0,0 +1,63 @@
+
+#include "hardware.h"
+
+#include <net/afsk.h>
+#include <cpu/irq.h>
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+
+/*
+ * Here we are using only one modem. If you need to receive
+ * from multiple modems, you need to define an array of contexts.
+ */
+static Afsk *ctx;
+
+void hw_afsk_adcInit(int ch, Afsk *_ctx)
+{
+	ctx = _ctx;
+	ASSERT(ch <= 5);
+
+	AFSK_STROBE_INIT();
+	AFSK_STROBE_OFF();
+	/* Set prescaler to clk/8 (2 MHz), CTC, top = ICR1 */
+	TCCR1A = 0;
+	TCCR1B = BV(CS11) | BV(WGM13) | BV(WGM12);
+	/* Set max value to obtain a 9600Hz freq */
+	ICR1 = ((CPU_FREQ / 8) / 9600) - 1;
+
+	/* Set reference to AVCC (5V), select CH */
+	ADMUX = BV(REFS0) | ch;
+
+	DDRC &= ~BV(ch);
+	PORTC &= ~BV(ch);
+	DIDR0 |= BV(ch);
+
+	/* Set autotrigger on Timer1 Input capture flag */
+	ADCSRB = BV(ADTS2) | BV(ADTS1) | BV(ADTS0);
+	/* Enable ADC, autotrigger, 1MHz, IRQ enabled */
+	/* We are using the ADC a bit out of specifications otherwise it's not fast enough for our
+	 * purposes */
+	ADCSRA = 	BV(ADEN) |	// ADC Enable
+				BV(ADSC) |	// ADC Start converting
+				BV(ADATE) | // Enable autotriggering
+				BV(ADIE) |  // ADC Interrupt enable
+				BV(ADPS2);  // Enable prescaler flag 2 (1-0-0 = division by 16 = 1MHz)
+}
+
+
+bool hw_afsk_dac_isr;
+
+/*
+ * This is how you declare an ISR.
+ */
+DECLARE_ISR(ADC_vect)
+{
+	TIFR1 = BV(ICF1);
+	afsk_adc_isr(ctx, ((int16_t)((ADC) >> 2) - 128));
+	if (hw_afsk_dac_isr)
+		PORTD = afsk_dac_isr(ctx) & 0xF0;
+	else
+		PORTD = 128;
+}