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/**

    @file soc.h

    @brief Hardware-dependent function library.

    This file encapsulates hardware access from the rest of the program for

    easier porting.

*/

#ifndef SOC_H_INCLUDED

#define SOC_H_INCLUDED

#include <stdint.h>

#include <stdbool.h>

/*-- SoC configuration macros ------------------------------------------------*/

/* These may optionally be set at the makefile */

#ifndef CLOCK_RATE

/** Default clock rate is that of Terasic's DE-1 board */

#define CLOCK_RATE (50e6)

#endif  

#ifndef TIMER0_PRESCALER

/** By default the prescaler is set to count periods of 20us @ 50MHz */

#define TIMER0_PRESCALER (1000)

#endif

/*-- Public functions --------------------------------------------------------*/

/*-- SoC ----------------------------------------------------------*/

/**

    Set up all the MCU peripherals with a standard cofiguration.

    This includes:

    -# Timer 0 set to count seconds (when prescaler set to 20us).

    -# UART in default configuration (19200-8-N-1).

*/

extern void soc_init(void);

/**

    Read millisecond counter.

    @return Number of milliseconds elapsed since last call to mcu_init.

*/

extern uint32_t soc_get_msecs(void);

/*-- CPU ----------------------------------------------------------*/

/**

    Enable or disable interrupts globally with EA flag.

    Does not affect any other interrupt flag.

    @arg enable 1 to enable interrupts, 0 to disable.

*/

extern void cpu_enable_interrupts(uint8_t enable);

/*-- Timer 0 ------------------------------------------------------*/

/**

    Initialize Timer 0.

    This function does not start the timer, only:

        -# Loads the T0ARL flag.

        -# Clears the T0IRQ flag.

        -# Loads the reload register.

    @arg reload Value for reload register, or 0xffff to not use reload mode.

*/

extern void timer0_init(uint16_t reload);

/**

    Start or stop Timer 0 by setting flag T0CEN.

    @arg enable 1 to start the timer, 0 to stop it.

*/

extern void timer0_enable(uint8_t enable);

/**

    Read value of Timer 0 counter register.

    Will make sure the value read is consistent.

    @return Value of Timer 0 counter register.

*/

extern uint16_t timer0_counter(void);

/**

    Enable or disable Timer 0 interrupt.

    Does not affect global EA flag.

    @arg enable 1 to enable interrupt, 0 to disable.

*/

extern void timer0_enable_irq(uint8_t enable);

/*-- Interrupt function prototypes --------------------------------*/

/*

    NOTE:

    SDCC requires that the prototype of all irq functions be present in the

    file that contains the main function.

*/

/**

    Interrupt response function for IRQ1 (Timer 0).

*/

void timer0_isr(void) __interrupt(1);

#endif