43 lines
1.3 KiB
C
43 lines
1.3 KiB
C
#include <stdint.h>
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#include <stdbool.h>
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#include "driverlib/sysctl.h"
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#include "driverlib/gpio.h"
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#include "driverlib/timer.h"
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#include "driverlib/pin_map.h"
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#include "inc/tm4c1294ncpdt.h"
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#include "driverlib/interrupt.h"
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#include "inc/hw_types.h"
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#include "inc/hw_memmap.h"
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#include "frequency.h"
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void start_frequency_scan() {
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// config GPIO PD0 as timer input T0CCP0 at BoosterPack Connector #1 pin 14
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SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);
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GPIOPinTypeTimer(GPIO_PORTD_BASE, GPIO_PIN_0);
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GPIOPinConfigure(GPIO_PD0_T0CCP0);
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SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
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TimerDisable(TIMER0_BASE, TIMER_BOTH);
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TimerConfigure(TIMER0_BASE, TIMER_CFG_SPLIT_PAIR | TIMER_CFG_A_CAP_TIME_UP);
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TimerControlEvent(TIMER0_BASE, TIMER_A, TIMER_EVENT_POS_EDGE);
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// use maximum load value
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TimerLoadSet(TIMER0_BASE, TIMER_A, 0xffff);
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// use maximum prescale value
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TimerPrescaleSet(TIMER0_BASE, TIMER_A, 0xff);
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TimerIntEnable(TIMER0_BASE, TIMER_CAPA_EVENT);
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TimerEnable(TIMER0_BASE, TIMER_A);
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}
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uint32_t previous;
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void capture_handler() {
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TimerIntClear(TIMER0_BASE, TIMER_CAPA_EVENT);
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uint32_t current = TimerValueGet(TIMER0_BASE, TIMER_A);
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uint32_t delta = current - previous;
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gPeriod = delta;
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previous = current;
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}
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