RISCV_TIMER USER GUIDE

REVISION HISTORY¶

Revision No.	Description	Date
1.0	Initial release	04/21/2023

1. OVERVIEW¶

Timer is a hardware module used in computer and microcontroller systems to measure time intervals or generate precise timing events. The basic working principle of a timer is to drive a counter through a clock source. When the counter reaches a preset value, an event is generated, usually through an interrupt to notify the processor.

2. KEYWORD DESCRIPTION¶

PM-timer

Timer powered by PM domain.
NonPMtimer

Timer powered by NonPM domain.
OneShoot mode

A working mode of Timer that triggers an interrupt when the timer reaches a certain time.
RunLoop mode

A working mode of Timer, which will reset the counting core and trigger a loop after the timer is triggered.

3. FUNCTION DESCRIPTION¶

Whether it is PM timer or NonPM timer, the use of timers has the same steps. From a development perspective, there are five steps involved

Register Timer
Start the timer
Interrupt functions for executing timers and processing functions for calling timers in the system
Stop timer
Unregister timer

In addition, when using a timer, the following factors need to be considered:：

Quantity of hardware
- 8 PM-timer
- 4 NonPM-timer
CLK
- PM-timer0 ~ PM-timer3 and NonPM-timers use the same clock, with a default frequency of 12MHz, PM timer4~PM timer7 each use different clocks.
- PM-timer0 ~ PM-timer3 each use different hardware interrupt numbers, while PM-timer4 ~ PM-timer7 use the same hardware interrupt number.
Limitation
- Software limitation: Riscv side and arm side cannot use the same timer at the same time, which may cause interrupt confusion.
working mode
- Timer has two working modes, one is oneshook mode and the other is RunLoop mode.

4. HARDWARE CONNECTION INTRODUCTION¶

NA

5. Usage Introduction In RTOS¶

5.1. DRIVER PATH¶

sc/driver/sysdriver/timer/drv/pub/drv_pm_timer.h
sc/driver/sysdriver/timer/drv/pub/drv_timer_api.h
sc/driver/sysdriver/timer/drv/pub/drv_timer.h
sc/driver/sysdriver/timer/drv/src/abi_headers_timer.c
sc/driver/sysdriver/timer/drv/src/drv_pm_timer.c
sc/driver/sysdriver/timer/drv/src/drv_timer.c
sc/driver/sysdriver/timer/drv/src/drv_timer_test.c

5.2. CONFIG Configuration¶

No configuration is required.

5.3. SYSDESC Configuration¶

No configuration is required.

5.4. Padmux Configuration¶

No configuration is required.

5.5. Sample code¶

static void timer_isr(void)
{
    CamOsPrintf("I am timer%d!\n", timer.timer_id);
}

int timer_teset(void)
{
    drv_timer_id timer_id = 1;
    u32 time = 20000;

    drv_timer_register_isr(timer_id, timer_isr);

    drv_timer_start(timer_id, time);

    CamOsMsSleep(20000);

    drv_timer_stop(timer_id);

    drv_timer_release_isr(timer_id)
}

5.6. UT case¶

1) Open timer to test the demo macro VER_TIMER

2) Test demo path: sc/driver/sysdriver/timer/drv/src/drv_timer_test.c

3) Perform testing

SS-RTOS # timer
Plz key in : timer [timerID] [time]
[timerID] 1 - timer1
          2 - timer2
          3 - timer3
          4 - timer4
          5 - timer5
          6 - timer4
          7 - timer5
[time] timing time(ms)
timer [timerId] [time]

Example:
  # timer 1 1000   /*Enable Timer 1, report an interrupt every 1000 ms, and report it 10 times.*/

6. API参考¶

This functional module provides the following interfaces:

API Name	Function
drv_timer_register_isr	Register timer interrupt function
drv_timer_release_isr	Release timer interrupt function
drv_timer_disable_intr	Disable timer interrupt function
drv_timer_enable_intr	Enable timer interrupt function
drv_timer_clear_intr	Clear timer interrupt
drv_timer_get_intr_status	Get timer interrupt status
drv_timer_stop	Stop timer
drv_timer_start	Start timer, unit ms
drv_timer_start_us	Start timer, unit us
drv_timer_get_timeout_length	Get the count value corresponding to the timer expiration time
drv_timer_get_count	Get the value of the timer from the start of the timer to the current timer counter
drv_timer_get_kickoff_time_us	Get how much time has passed since the timer started, unit us

6.1. drv_timer_register_isr¶

Function

Register timer interrupt function

Grammar

static inline void drv_timer_register_isr(drv_timer_id timer_id, timer_isr_t isr)

Parameters

Parameter Name Description

timer_id timer ID

isr Interrupt function
Return value

Return value Description

NA NA

6.2. drv_timer_release_isr¶

Function

Release timer interrupt function

Grammar

static inline void drv_timer_release_isr(drv_timer_id timer_id)

Parameters

Parameter Name Description

timer_id timer ID
Return value

Return value Description

NA NA

6.3. drv_timer_disable_intr¶

Function

Disable timer interrupt function

Grammar

static inline void drv_timer_disable_intr(drv_timer_id timer_id)

Parameters

Parameter Name Description

timer_id timer ID
Return value

Return value Description

NA NA

6.4. drv_timer_enable_intr¶

Function

Enable timer interrupt function.

Grammar

static inline void drv_timer_enable_intr(drv_timer_id timer_id)

Parameters

Parameter Name Description

timer_id timer ID
Return value

Return value Description

NA NA

6.5. drv_timer_clear_intr¶

Function

Clear timer interrupt

Grammar

static inline void drv_timer_clear_intr(drv_timer_id timer_id)

Parameters

Parameter Name Description

timer_id timer ID
Return value

Return value Description

NA NA

6.6. drv_timer_get_intr_status¶

Function

Get timer interrupt status

Grammar

static inline u32 drv_timer_get_intr_status(drv_timer_id timer_id)

Parameters

Parameter Name Description

timer_id timer ID
Return value

Return value Description

NA NA

6.7. drv_timer_stop¶

Function

Stop timer

Grammar

static inline void drv_timer_stop(drv_timer_id timer_id)

Parameters

Parameter Name Description

timer_id timer ID
Return value

Return value Description

NA NA

6.8. drv_timer_start¶

Function

Start timer. (The minimum unit of the timer's expiration time is 1 ms.)

Grammar

static inline void drv_timer_start(drv_timer_id timer_id, u32 expect_time)

Parameters

Parameter Name Description

timer_id timer ID

expect_time Timer expiration time(ms)
Return value

Return value Description

NA NA

6.9. drv_timer_start_us¶

Function

Start timer. (The minimum unit of the timer's expiration time is 1 us.)

Grammar

static inline void drv_timer_start_us(drv_timer_id timer_id, u32 expect_time)

Parameters

Parameter Name Description

timer_id timer ID

expect_time Timer expiration time(us)
Return value

Return value Description

NA NA

6.10. drv_timer_get_timeout_length¶

Function

Get the count value corresponding to the timer expiration time

Grammar

static inline u32 drv_timer_get_timeout_length(drv_timer_id timer_id)

Parameters

Parameter Name Description

timer_id timer ID
Return value

Return value Description

NA NA

6.11. drv_timer_get_count¶

Function

Get the value of the timer from the start of the timer to the current timer counter

Grammar

static inline u32 drv_timer_get_count(drv_timer_id timer_id)

Parameters

Parameter Name Description

timer_id timer ID
Return value

Return value Description

u32 Get the value on the timer counter from the start of the timer until now

6.12. drv_timer_get_kickoff_time_us¶

Function

How much time has passed since the timer was started.

Grammar

static inline u32 drv_timer_get_kickoff_time_us(drv_timer_id timer_id)

Parameters

Parameter Name Description

timer_id timer ID
Return value

Return value Description

u32 How much time has passed since the timer was started, unit is us