High Resolution Timer

High Resolution Timer Platform interface

HR Timer Overview

High-resolution timers operate using high-frequency clock signals derived from system clocks or dedicated oscillators. The timer counts clock cycles to measure time or trigger actions, with its precision determined by the clock frequency.

Application Interface

Users can directly call the API’s though most of them will be called by device drivers.

The below table captures the functions that are to be called from the application layer.

API Functions
Function	Description
rs_hr_timer_open	To open the hr timer interface.
rs_hr_timer_start	To start the timer for the given channel
rs_hr_timer_stop	To stops the timer for the given channel
rs_hr_timer_get_count	To get count from hr timer.
rs_hr_timer_close	To close the timer unit

Error Code

Every API’s for the HR Timer returns some success or failure values. Please refer below section,

RAPIDSEA ERROR CODES

Documentation from the relevant header as follows:

Defines

RS_HR_TIMER_TRIGGER_MODE_CONTINUOUS: Set Trigger Mode Increment continuously

RS_HR_TIMER_TRIGGER_MODE_EXTERNAL: Increment via external event.

RS_HR_TIMER_OPERATION_MODE_INPUT_CAPTURE: Operation mode Capture input events

RS_HR_TIMER_OPERATION_MODE_OUTPUT_COMPARE: Use for output compare.

RS_HR_TIMER_OPERATION_MODE_EDGE_PWM: Generate Edge aligned PWM.

RS_HR_TIMER_OPERATION_MODE_CENTER_PWM: Generate Center aligned PWM.

RS_HR_TIMER_OPERATION_MODE_ONE_PULSE: One pulse mode.

RS_HR_TIMER_EVENT_TYPE_COUNTER_OVERFLOW: Event Type On Counter Overflow

RS_HR_TIMER_EVENT_TYPE_COUNTER_UNDERFLOW: On Counter Underflow.

RS_HR_TIMER_EVENT_TYPE_INPUT_CAPTURE: When an input event happened.

RS_HR_TIMER_WIDTH_8_BIT: Timer resolution 8 bit resolution

RS_HR_TIMER_WIDTH_16_BIT: 16 bit resolution

RS_HR_TIMER_WIDTH_24_BIT: 24 bit resolution

RS_HR_TIMER_WIDTH_32_BIT: 32 bit resolution

RS_HR_TIMER_WIDTH_64_BIT: 64 bit resolution

RS_HR_TIMER_NS_RESOLUTION: Counter Resolution Set counter resolution as nano seconds

RS_HR_TIMER_US_RESOLUTION: Set counter resolution as micro seconds.

RS_HR_TIMER_MS_RESOLUTION: Set counter resolution as milli seconds.

RS_HR_TIMER_S_RESOLUTION: Set counter resolution as seconds.

Typedefs

typedef struct tag_rs_hr_timer_config rs_hr_timer_config_t: Structure for setting up each Timer Channel configuration.

typedef struct tag_rs_hr_timer_instance rs_hr_timer_instance_t: Structure for high resolution timer instance.

Functions

rs_handle_t rs_hr_timer_open(rs_hr_timer_instance_t *ptr_hr_timer_instance, rs_hr_timer_config_t *ptr_hr_timer_config)

Function Declarations.

Configures the Timer Unit

This function configures/reconfigures the Timer Unit as per the given configuration

Parameters:

ptr_hr_timer_instance – [in] - Pointer to the instance structure
ptr_hr_timer_config – [in] - Pointer to the configuration structure

Returns:

0 on success or error code on failure

rs_handle_t rs_hr_timer_set_config(rs_hr_timer_config_t *ptr_hr_timer_config, uint8_t u8_unit_index, uint8_t u8_resolution, uint8_t u8_width, uint32_t u32_frequency)

Configures the high-resolution timer.

This function sets the configuration parameters for the high-resolution timer

Parameters:

ptr_hr_timer_config – [in] - Pointer to a structure that holds the high-resolution timer configuration.
u8_unit_index – [in] - The index of the timer unit to configure.
u8_resolution – [in] - he resolution to set for the timer (e.g., 8-bit, 16-bit, etc.).
u8_width – [in] - The width (size) of the timer in bits
u32_frequency – [in] - The frequency of the timer in Hz.

Returns:

0 on success or error code on failure

rs_ret_val_t rs_hr_timer_start(rs_handle_t handle)

rs_ret_val_t rs_hr_timer_stop(rs_handle_t handle)

Stops the timer for the given channel.

This function stops the timer operation for the given channel

Parameters:: handle – [in] - Handle to the Timer unit
Returns:: 0 on success or error code on failure

rs_ret_val_t rs_hr_timer_get_count(rs_handle_t handle, void *ptr_value)

Get count from hr timer.

This function get count from hr timer.

Parameters:

handle – [in] - Handle to the Timer Unit.
ptr_value – [out] - pointer to the counter.

Returns:

None.

rs_ret_val_t rs_hr_timer_close(rs_handle_t handle)

Closes the timer unit.

This function un-initializes the Timer Unit and releases the handle

Parameters:: handle – [in] - Handle to the Timer Unit
Returns:: 0 on success or error code on failure

struct tag_rs_hr_timer_config

#include <rs_hr_timer.h>

Structure for setting up each Timer Channel configuration.

Public Members

uint8_t unit_index: Index to Timer unit as defined by underlying HAL layer.

uint8_t resolution: Resolution of the counter - us, ns.

uint8_t width: Width.

uint8_t reserved: Reserved.

uint32_t frequency: Timer Frequency.

struct tag_rs_hr_timer_instance

#include <rs_hr_timer.h>

Structure for high resolution timer instance.

Public Members

rs_hr_timer_config_t *ptr_hr_timer_config: Pointer to the HR timer configuration.

uint32_t u32_hr_timer_counter: HR Timer counter.