GR5xx Timers
1. Overview of GR5xx Timers
| 名字 | 模块属性 | AON域 | 个数 | 时钟源 | 计数模式和计时精度 | 驱动参考 | 典型特点 | 应用场景 |
|---|---|---|---|---|---|---|---|---|
| SysTick | ARM系统 | NO | 1 | System Clock | 递减，24-bit | 标准的CMSIS 驱动 | 24位系统硬件定时器, 注意使用时预防溢出 | 1. 可作为OS的Tick心跳, 方便不同Cortex核之间移植 2.在GR551x 的FreeRTOS 工程中的Active模式, 作为 OS的Tick 驱动使用; 3.在非GR551x芯片系列的FreeRTOS工程 没有使用SysTick（用RTC）, 所以Systick可以根据需要提供给应用层使用 |
| DWT | ARM系统 | NO | 1 | System Clock | 递增，32-bit | HAL_TIMEOUT_INIT HAL_TIMEOUT_GET_TICK HAL_TIMEOUT_DEINIT |
不算标准Timer, 主要用于 系统tick 计数 | 1.可以使用 DWT的Tick来辅助计算片段代码的运行时间 2.注意溢出时间, 举例96MHz主频下, 溢出时间约 U32_Max/96M = 44秒. 使用场景一般都先重置再使用, 尽量不要跨越复杂的上下文环境使用 |
| Timer | ARM系统 | NO | 2 | System Clock | 递减，32-bit | HAL：gr55xx_hal_tim.c/h APP:app_tim.c/h |
1.32-bit硬件定时器 2.MCU睡眠定时器不能工作，所以调用接口初始化了系统不会睡眠，反初始化才允许系统睡眠 3.GR533x的timer有IO捕获功能 |
MCU ACTIVE模式下高精度定时场景< |
| Dual Timer | ARM系统 | NO | 2 | System Clock | 递减，32-bit | HAL:gr55xx_hal_dual_tim.c/h APP:app_dual_tim.c/h |
1.可用作16/32 位定时器 2.MCU睡眠定时器不能工作，所以调用接口初始化了系统不会睡眠，反初始化才允许系统睡眠 3.有周期模式、自由模式、一次到达等多种定时模式 4.GR533x的dual timer拥有IO联动功能 |
1. MCU ACTIVE模式下高精度定时场景 2.用于捕获IO电平变化信息 3.用于产生时序严格的IO方波 |
| ARM-WDT | ARM系统 | NO | 1 | System Clock | 递减，32-bit | CMSIS驱动 | ARM 看门狗, 不能在Sleep模式工作 | 基本弃用状态 |
| AON-WDT | SOC always on域 | YES | 1 | 慢速时钟源，具体配置见项目2 | 递减，32-bit | HAL gr55xx_hal_aon_wdt.c/h APP app_aon_wdt.c/h |
1. 32Bit硬件计数器, 触发系统复位, MCU 睡眠也可继续工作 2.在复位前可以配置一个过期提醒ALARM中断 |
1. 用作系统的软件看门狗 2.用作特别设计的系统复位接口 3.ALARM中断可以用来记录看门狗复位前的现场信息供分析 |
| Sleep Timer APP Timer |
SOC always on域 | YES | 1 | 慢速时钟源，具体配置见项目2 | 递减，32-bit | HAL gr55xx_hal_sleep_timer.c/h APP app_timer.c/h |
1. 32Bit 硬件计数器 2.模式0 - 休眠模式计数活动模式停止工作 3.模式1 - 单次计数,完成停止, 无论是休眠还是活动模式 4.模式2 - 类似模式1, 自动重载计数 |
1. 可用作将CPU从休眠状态唤醒 2. 基于sleep timer构建的应用层timer （即app timer）, 可广泛应用在对时间精度要求不是很高的场景做定时器(支持休眠下工作). 3. 应用层Timer 用软件链表管理, 因此存在一定的时延 |
| RTC Calendar |
SOC always on域 | YES | GR551x/GR533x:1 GR5525/GR5526:2 |
慢速时钟源，具体配置见项目2 | 递增，32-bit | HAL gr55xx_hal_rtc.c/h APP app_rtc.c/h |
1.采用外部晶振时候计时精度等于晶振ppm 2.GR551x 如果采用RNG2做时钟源, Calendar无法使用, 因为其无法正常设置RNG2为时钟源 3.5526用RNG2为时钟源也无法使用Calendar, 因为RNG2计数有时突变到0xffffffff |
1. 一个替代SysTick作为 OS的Tick心跳（Active下周期性, Sleep 单次计时） 2.另一个 实现日历，有计时、tick中断和闹钟设置功能 |
| PWM | SOC外围模块 | NO | 2 | Serial Clock | 递增，32-bit | HAL gr55xx_hal_pwm.c/h APP app_pwm.c/h |
为外设提供PWM 信号 | 电机、LED控制或信号发生等场景 |
| BLE_Timer ble comm timer |
SOC ble模块 | YES | 1 | 慢速时钟源，具体配置见项目2 | / | ble_time.c/h | ble core 里面的定时器 | 为协议栈提供广播间隔等时隙，系统也可以调它的接口获取睡眠时间 |
2. Clock configuration of GR5xx slow clock timers
GR5xx slow clock based timers are BLE_Timer, aon_wdt, sleep timer, RTC respectively.
The slow clock sources are external crystal clock and internal RC clock respectively.
The external crystal clock is a 32K crystal oscillator, also called LFXO-32K, characterized by better stability than the internal RC clock.
The internal RC clocks are RNG_OSC and LFRC-32K (also called RNG2).The RNG_OSC comes from the 2MHZ_RNG_OS on the clock tree, which is less stable, while the LFRC-32K has a better PPM compared to the RNG_OSC.However, when the LFRC-32K is used for the timing module on the GR551x and the GR5526, there is a problems with abrupt timing changes, so it can’t be used. The slow clock configuration for each chip is as follows:
For GR551x:
BLE TIMER: LFXO_32K if external clock source is selected, RNG2 if internal clock source is selected. AON WDT:fixed to RNG (RNG2 is not supported, nor is external LFXO_32K) SLEEP TIMER:LFXO_32K for external, RNG2 for internal. RTC: fixed to external LFXO_32K, no support for internal clock (so if the chip does not have external LFXO_32K, the SDK implements calendar timing based on ble timer, but the calendar does not have tick and alarm functions)
For GR5526.
BLE Timer: use LFXO_32K if external clock source is selected, use LFRC_32K if internal clock source is selected. AON WDT: LFXO_32K if external clock source is selected, RNG_OSC if internal clock source is selected (LFRC_32K cannot be used due to mutation in timing). Sleep Timer: LFXO_32K if external clock source is selected, RNG_OSC if internal clock source is selected (cannot be used because LFRC_32K timing has mutation) RTC0:if choose external clock source with LFXO_32K, if choose internal clock source when app_rtc.c will implement calendar simple time timing function based on ble_timer, no tick and alarm interrupt function. RTC1: use LFXO_32K if external clock source is selected, use RNG_OSC if internal clock source is selected (can’t use LFRC_32K timing since it has mutation).
For GR5525/GR533x:
For GR5525/GR533x: For all BLE_Timer/aon_wdt/sleep timer/RTC.
For all BLE_Timer/aon_wdt/sleep timer/RTC, use LFXO_32K if external clock source is selected, and use LFRC_32K if internal clock source is selected (because LFRC-32K has better PPM than RNG_OSC).
3. RTOS tick implementation of each chip
GR551x:
In MCU ACTIVE mode, the RTOS tick is realized based on Systick;
In MCU SLEEP mode, systick stops working and relies on the timing task of ble_timer to wake up, and compensates systick by reading the time of ble_timer after waking up.
GR5525/GR5526
RTOS tick implementation based on RTC1. these two chips have two RTCs, so RTC0 is used for normal calendar functions.
GR533x:
Implement RTOS tick based on RTC0. Since the chip has only one way RTC, the calendar function will be limited in RTOS scenario.