Real-time Timer (RTT)

The Real-time Timer is built around a 32-bit counter used to count roll-over events of the programmable 16-bit prescaler, which enables counting elapsed seconds from a 32 kHz slow clock source.

This is a driver for configuration and use of the RTT peripheral.

Functions
void	rtt_disable (Rtt *p_rtt)
	Disable RTT. More...
void	rtt_disable_interrupt (Rtt *p_rtt, uint32_t ul_sources)
	Disable RTT interrupts. More...
void	rtt_enable (Rtt *p_rtt)
	Enable RTT. More...
void	rtt_enable_interrupt (Rtt *p_rtt, uint32_t ul_sources)
	Enable RTT interrupts. More...
uint32_t	rtt_get_status (Rtt *p_rtt)
	Get the status register value of the given RTT. More...
uint32_t	rtt_init (Rtt *p_rtt, uint16_t us_prescaler)
	Initialize the given RTT. More...
uint32_t	rtt_read_timer_value (Rtt *p_rtt)
	Read the current value of the RTT timer value. More...
void	rtt_sel_source (Rtt *p_rtt, bool is_rtc_sel)
	Select RTT counter source. More...
uint32_t	rtt_write_alarm_time (Rtt *p_rtt, uint32_t ul_alarm_time)
	Configure the RTT to generate an alarm at the given time. More...

Variables
static uint32_t	g_wobits_in_rtt_mr = 0

void rtt_disable

(

Rtt *

p_rtt

)

Disable RTT.

Parameters

p_rtt

Pointer to an RTT instance.

References g_wobits_in_rtt_mr.

void rtt_disable_interrupt	(	Rtt *	p_rtt,
		uint32_t	ul_sources
	)

Disable RTT interrupts.

Parameters

p_rtt	Pointer to an RTT instance.
ul_sources	Interrupts to be disabled.

References g_wobits_in_rtt_mr.

Referenced by rtt_write_alarm_time().

void rtt_enable

(

Rtt *

p_rtt

)

Enable RTT.

Parameters

p_rtt

Pointer to an RTT instance.

References g_wobits_in_rtt_mr.

void rtt_enable_interrupt	(	Rtt *	p_rtt,
		uint32_t	ul_sources
	)

Enable RTT interrupts.

Parameters

p_rtt	Pointer to an RTT instance.
ul_sources	Interrupts to be enabled.

References g_wobits_in_rtt_mr.

Referenced by configure_rtt(), and rtt_write_alarm_time().

uint32_t rtt_get_status

(

Rtt *

p_rtt

)

Get the status register value of the given RTT.

Parameters

p_rtt

Pointer to an RTT instance.

Returns

The Real-time Timer status.

Referenced by RTT_Handler().

uint32_t rtt_init	(	Rtt *	p_rtt,
		uint16_t	us_prescaler
	)

Initialize the given RTT.

Note

This function restarts the real-time timer. If w_prescaler is equal to zero, the prescaler period is equal to 2^16 * SCLK period. If not, the prescaler period is equal to us_prescaler * SCLK period.

Parameters

p_rtt	Pointer to an RTT instance.
us_prescaler	Prescaler value for the RTT.

Returns

0 if successful.

References g_wobits_in_rtt_mr.

Referenced by configure_rtt().

uint32_t rtt_read_timer_value

(

Rtt *

p_rtt

)

Read the current value of the RTT timer value.

Parameters

p_rtt

Pointer to an RTT instance.

Returns

The current Real-time Timer value.

Referenced by configure_rtt(), and refresh_display().

void rtt_sel_source	(	Rtt *	p_rtt,
		bool	is_rtc_sel
	)

Select RTT counter source.

Parameters

p_rtt	Pointer to an RTT instance.
is_rtc_sel	RTC 1Hz Clock Selection.

References g_wobits_in_rtt_mr.

Referenced by configure_rtt().

uint32_t rtt_write_alarm_time	(	Rtt *	p_rtt,
		uint32_t	ul_alarm_time
	)

Configure the RTT to generate an alarm at the given time.

alarm happens when CRTV value equals ALMV+1, so RTT_AR should be alarmtime - 1. if you want to get alarm when rtt hit 0 , ALMV should be set to 0xFFFFFFFF.

Parameters

p_rtt	Pointer to an RTT instance.
ul_alarm_time	Alarm time,Alarm time = ALMV + 1.

Return values

0	Configuration is done.

Alarm time = ALMV + 1,If the incoming parameter is 0, the ALMV is set to 0xFFFFFFFF.

References rtt_disable_interrupt(), and rtt_enable_interrupt().

Referenced by main().

uint32_t g_wobits_in_rtt_mr = 0

static

Referenced by rtt_disable(), rtt_disable_interrupt(), rtt_enable(), rtt_enable_interrupt(), rtt_init(), and rtt_sel_source().