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Updated doc. Cleanup.

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This commit is contained in:
Mark Qvist 2014-04-09 23:33:15 +02:00
parent 65820627ec
commit 5452a7f662
6 changed files with 74 additions and 67 deletions
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21
Modem/hardware.c
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@ -17,6 +17,10 @@ static Afsk *modem;
// And now for the actual hardware functions //
//////////////////////////////////////////////////////
// M1 correction = 9500
// M2 correction = 40000
#define FREQUENCY_CORRECTION 0
// This function initializes the ADC and configures
// it the way we need.
void hw_afsk_adcInit(int ch, Afsk *_modem)
@ -28,15 +32,19 @@ void hw_afsk_adcInit(int ch, Afsk *_modem)
// a pin that can't be used for analog input
ASSERT(ch <= 5);
// We need to do some configuration on the Timer/Counter Control
// Register 1, aka Timer1
// We need a timer to control how often our sampling functions
// should run. To do this we will need to change some registers.
// First we do some configuration on the Timer/Counter Control
// Register 1, aka Timer1.
//
// The following bits are set:
// CS11: ClockSource 11, sets the prescaler to 8, ie 2MHz
// WGM13 and WGM12 together enables Timer Mode 12, which
// CS10: ClockSource 10, sets no prescaler on the clock,
// meaning it will run at the same speed as the CPU, ie 16MHz
// WGM13 and WGM12 together enables "Timer Mode 12", which
// is Clear Timer on Compare, compare set to TOP, and the
// source for the TOP value is ICR1 (Input Capture Register1).
TCCR1A = 0;
TCCR1B = BV(CS11) | BV(WGM13) | BV(WGM12);
TCCR1B = BV(CS10) | BV(WGM13) | BV(WGM12);
// Then we set the ICR1 register to what count value we want to
// reset (and thus trigger the interrupt) at.
@ -47,7 +55,8 @@ void hw_afsk_adcInit(int ch, Afsk *_modem)
// (CPUClock / Prescaler) / desired frequency - 1
// So that's what well put in this register to set up our
// 9.6KHz sampling rate.
ICR1 = ((CPU_FREQ / 8) / 9600) - 1;
ICR1 = (((CPU_FREQ+FREQUENCY_CORRECTION)) / 9600) - 1;
kprintf("ICR1=%d",ICR1);
// Set reference to AVCC (5V), select pin
// Set the ADMUX register. The first part (BV(REFS0)) sets