timer.c File Reference

#include "timer.h"
#include "power.h"
#include <LPC17xx.h>
#include <stdlib.h>

Go to the source code of this file.

Functions
_PRIVATE void	set_match_reg (LPC_TIM_TypeDef *const timer, const TIMER_MatchRegister match_reg)
_PRIVATE void	unset_match_reg (LPC_TIM_TypeDef *const timer, const TIMER_MatchRegister match_reg)
_PRIVATE void	clear_match_regs (LPC_TIM_TypeDef *const timer)
void	TIMER_Init (TIMER *timer, u8 which, u32 prescaler, u8 int_priority)
	Initializes a TIMER peripheral.
void	TIMER_Deinit (TIMER timer)
	Deconfigures a TIMER peripheral (also match registers).
void	TIMER_SetMatch (TIMER timer, TIMER_MatchRegister match_reg)
	Sets the match value for a match register of a TIMER peripheral.
void	TIMER_UnsetMatch (TIMER timer, TIMER_MatchRegister match_reg)
	Unsets a match register of a TIMER peripheral.
void	TIMER_Enable (TIMER timer)
	Enables a TIMER peripheral.
void	TIMER_Disable (TIMER timer)
	Disables a TIMER peripheral.
bool	TIMER_IsEnabled (TIMER timer)
	Checks if a TIMER peripheral is enabled.
void	TIMER_Reset (TIMER timer)
	Resets a TIMER peripheral without deconfiguring it.
u32	TIMER_ReadValue (TIMER timer)
	Reads the current value of a TIMER peripheral.

Function Documentation

clear_match_regs()

_PRIVATE void clear_match_regs

(

LPC_TIM_TypeDef *const

timer

)

Definition at line 51 of file timer.c.

{
    timer->MR0 = 0;
    timer->MR1 = 0;
    timer->MR2 = 0;
    timer->MR3 = 0;
    timer->MCR = 0;
}

set_match_reg()

_PRIVATE void set_match_reg	(	LPC_TIM_TypeDef *const	timer,
		const TIMER_MatchRegister	match_reg
	)

Definition at line 9 of file timer.c.

{
    switch (match_reg.which)
    {
    case 0:
        timer->MR0 = match_reg.match;
        break;
    case 1:
        timer->MR1 = match_reg.match;
        break;
    case 2:
        timer->MR2 = match_reg.match;
        break;
    case 3:
        timer->MR3 = match_reg.match;
        break;
    }
 
    timer->MCR |= match_reg.actions << (3 * match_reg.which);
}

TIMER_Deinit()

void TIMER_Deinit

(

TIMER

timer

)

Deconfigures a TIMER peripheral (also match registers).

Note

In order to use the TIMER peripheral again, it must be initialized.

Definition at line 124 of file timer.c.

{
    TIMER_Disable(timer);
    TIMER_Reset(timer);
 
    switch (timer.which)
    {
    case 0:
        POWER_TurnOffPeripheral(POW_PCTIM0);
 
        LPC_TIM0->PR = 0;
        clear_match_regs(LPC_TIM0);
        NVIC_DisableIRQ(TIMER0_IRQn);
        break;
    case 1:
        POWER_TurnOffPeripheral(POW_PCTIM1);
 
        LPC_TIM1->PR = 0;
        clear_match_regs(LPC_TIM1);
        NVIC_DisableIRQ(TIMER1_IRQn);
        break;
    case 2:
        POWER_TurnOffPeripheral(POW_PCTIM2);
 
        LPC_TIM2->PR = 0;
        clear_match_regs(LPC_TIM2);
        NVIC_DisableIRQ(TIMER2_IRQn);
        break;
    case 3:
        POWER_TurnOffPeripheral(POW_PCTIM3);
 
        LPC_TIM3->PR = 0;
        clear_match_regs(LPC_TIM3);
        NVIC_DisableIRQ(TIMER3_IRQn);
        break;
    }
}

TIMER_Disable()

void TIMER_Disable

(

TIMER

timer

)

Disables a TIMER peripheral.

Parameters

timer

TIMER peripheral

Definition at line 229 of file timer.c.

{
    switch (timer.which)
    {
    case 0:
        CLR_BIT(LPC_TIM0->TCR, 0);
        break;
    case 1:
        CLR_BIT(LPC_TIM1->TCR, 0);
        break;
    case 2:
        CLR_BIT(LPC_TIM2->TCR, 0);
        break;
    case 3:
        CLR_BIT(LPC_TIM3->TCR, 0);
        break;
    }
}

TIMER_Enable()

void TIMER_Enable

(

TIMER

timer

)

Enables a TIMER peripheral.

Parameters

timer

TIMER peripheral

Definition at line 203 of file timer.c.

{
    // NB: Check if the reset bit is set in TCR. If so,
    // clear it otherwise the timer will never start.
 
    switch (timer.which)
    {
    case 0:
        CLR_BIT(LPC_TIM0->TCR, 1); // Clear reset bit
        SET_BIT(LPC_TIM0->TCR, 0);
        break;
    case 1:
        CLR_BIT(LPC_TIM1->TCR, 1);
        SET_BIT(LPC_TIM1->TCR, 0);
        break;
    case 2:
        CLR_BIT(LPC_TIM2->TCR, 1);
        SET_BIT(LPC_TIM2->TCR, 0);
        break;
    case 3:
        CLR_BIT(LPC_TIM3->TCR, 1);
        SET_BIT(LPC_TIM3->TCR, 0);
        break;
    }
}

TIMER_Init()

void TIMER_Init	(	TIMER *	timer,
		u8	which,
		u32	prescaler,
		u8	int_priority
	)

Initializes a TIMER peripheral.

Parameters

timer	[OUTPUT] Configured TIMER peripheral
which	Which timer to initialize (0-3)
prescaler	Prescaler value. If set to NO_PRESCALER, prescaler won't be used.
int_priority	Timer interrupt priority (0 (highest), 15 (lowest)). If set to INT_PRIO_DEF, the default priority is set.

Definition at line 62 of file timer.c.

{
    if (!timer)
        return;
 
    bool valid_prio = !IS_DEF_PRIORITY(int_priority) && IS_BETWEEN_EQ(int_priority, 0, 15);
    bool valid_prescaler = !IS_NO_PRESCALER(prescaler);
 
    switch (which)
    {
    case 0:
        POWER_TurnOnPeripheral(POW_PCTIM0);
 
        if (valid_prescaler)
            LPC_TIM0->PR = prescaler;
 
        NVIC_EnableIRQ(TIMER0_IRQn);
 
        if (valid_prio)
            NVIC_SetPriority(TIMER0_IRQn, int_priority);
        break;
    case 1:
        POWER_TurnOnPeripheral(POW_PCTIM1);
 
        if (valid_prescaler)
            LPC_TIM1->PR = prescaler;
 
        NVIC_EnableIRQ(TIMER1_IRQn);
 
        if (valid_prio)
            NVIC_SetPriority(TIMER1_IRQn, int_priority);
        break;
    case 2:
        POWER_TurnOnPeripheral(POW_PCTIM2);
 
        if (valid_prescaler)
            LPC_TIM2->PR = prescaler;
 
        NVIC_EnableIRQ(TIMER2_IRQn);
 
        if (valid_prio)
            NVIC_SetPriority(TIMER2_IRQn, int_priority);
        break;
    case 3:
        POWER_TurnOnPeripheral(POW_PCTIM3);
 
        if (valid_prescaler)
            LPC_TIM3->PR = prescaler;
 
        NVIC_EnableIRQ(TIMER3_IRQn);
 
        if (valid_prio)
            NVIC_SetPriority(TIMER3_IRQn, int_priority);
        break;
    default:
        timer = NULL; // Invalid timer number
    }
 
    timer->which = which;
    timer->prescaler = prescaler;
}

TIMER_IsEnabled()

bool TIMER_IsEnabled

(

TIMER

timer

)

Checks if a TIMER peripheral is enabled.

Parameters

timer

TIMER peripheral

Returns

true if the TIMER peripheral is enabled, false otherwise

Definition at line 248 of file timer.c.

{
    switch (timer.which)
    {
    case 0:
        return IS_BIT_SET(LPC_TIM0->TCR, 0);
    case 1:
        return IS_BIT_SET(LPC_TIM1->TCR, 0);
    case 2:
        return IS_BIT_SET(LPC_TIM2->TCR, 0);
    case 3:
        return IS_BIT_SET(LPC_TIM3->TCR, 0);
    }
 
    return false;
}

TIMER_ReadValue()

u32 TIMER_ReadValue

(

TIMER

timer

)

Reads the current value of a TIMER peripheral.

Parameters

timer

TIMER peripheral

Returns

Current value of the TIMER peripheral

Definition at line 285 of file timer.c.

{
    switch (timer.which)
    {
    case 0:
        return LPC_TIM0->TC;
    case 1:
        return LPC_TIM1->TC;
    case 2:
        return LPC_TIM2->TC;
    case 3:
        return LPC_TIM3->TC;
    }
 
    return 0;
}

TIMER_Reset()

void TIMER_Reset

(

TIMER

timer

)

Resets a TIMER peripheral without deconfiguring it.

Note

In order to use the TIMER peripheral again, it must be enabled.

Definition at line 265 of file timer.c.

{
    // Reset: bit 1 in TCR (bit 0 is left untouched)
    switch (timer.which)
    {
    case 0:
        SET_BIT(LPC_TIM0->TCR, 1);
        break;
    case 1:
        SET_BIT(LPC_TIM1->TCR, 1);
        break;
    case 2:
        SET_BIT(LPC_TIM2->TCR, 1);
        break;
    case 3:
        SET_BIT(LPC_TIM3->TCR, 1);
        break;
    }
}

TIMER_SetMatch()

void TIMER_SetMatch	(	TIMER	timer,
		TIMER_MatchRegister	match_reg
	)

Sets the match value for a match register of a TIMER peripheral.

Parameters

match_reg

Match register to set

Definition at line 162 of file timer.c.

{
    if (match_reg.which >= MR_COUNT || match_reg.which < 0)
        return;
 
    switch (timer.which)
    {
    case 0:
        set_match_reg(LPC_TIM0, match_reg);
        break;
    case 1:
        set_match_reg(LPC_TIM1, match_reg);
        break;
    case 2:
        set_match_reg(LPC_TIM2, match_reg);
        break;
    case 3:
        set_match_reg(LPC_TIM3, match_reg);
        break;
    }
}

TIMER_UnsetMatch()

void TIMER_UnsetMatch	(	TIMER	timer,
		TIMER_MatchRegister	match_reg
	)

Unsets a match register of a TIMER peripheral.

Parameters

match_reg

Match register to unset. This variable won't be touched.

Definition at line 184 of file timer.c.

{
    switch (timer.which)
    {
    case 0:
        unset_match_reg(LPC_TIM0, match_reg);
        break;
    case 1:
        unset_match_reg(LPC_TIM1, match_reg);
        break;
    case 2:
        unset_match_reg(LPC_TIM2, match_reg);
        break;
    case 3:
        unset_match_reg(LPC_TIM3, match_reg);
        break;
    }
}

unset_match_reg()

_PRIVATE void unset_match_reg	(	LPC_TIM_TypeDef *const	timer,
		const TIMER_MatchRegister	match_reg
	)

Definition at line 30 of file timer.c.

{
    switch (match_reg.which)
    {
    case 0:
        timer->MR0 = 0;
        break;
    case 1:
        timer->MR1 = 0;
        break;
    case 2:
        timer->MR2 = 0;
        break;
    case 3:
        timer->MR3 = 0;
        break;
    }
 
    timer->MCR &= ~(match_reg.actions << (3 * match_reg.which));
}