问题: C5515 RTC Only 模式下, RTC Alarm无法唤醒系统.

专家,你好!

C5515的datasheet, system user guide, RTC user guide 以及网站上, 都提及到RTC only模式下,  如果要唤醒系统,需要在wakeup pin上面加高电平,

脉冲时间需要超过30.5us.   唤醒系统的方式包括, 外部wakeup pin手工置高电平,  RTC Alarm 和RTC periodic interrupt 三种方式.

我们手工方式成功了, 因为手工情况下将wakeu pin置高电平很容易操作, 持续时间容易控制.  

但是通过RTC Alarm 和 RTC periodic interrup均不能唤醒系统, 但观察到LED瞬间变亮

又变暗的情况, 以及系统电流上升和下降的瞬间.  我们严重怀疑是high pulse 的时间太短.

请问, 我们该怎么办?  RTC Alarm 产生的高电平脉冲宽度, 是否可以进行调整, 该如何调整?

官方说法: processors.wiki.ti.com/.../C55xx_RTC_ONLY_MODE_SUPPORT

RTC only mode Wake-Up:

A high pulse for a minimum of one RTC clock period (30.5 μs) to the WAKEUP pin is required to wake up the device from the RTC only mode.
WAKEUP Behavior

• A pulse (≥ 30.5 μs) must be applied to the WAKEUP pin (active high). When the WAKEUP pin is asserted, the voltage on the DSP_LDOO pin will start ramping up and it is monitored by the internal POR. Until the voltage reaches to the threshold level, the internal POR will hold the internal POWERGOOD signal low, which provides isolation to RTC during transition period. Once the voltage reaches to the threshold level, the internal POR asserts the internal POWERGOOD signal (logic level high) and it releases reset of the system and disables RTC isolation and enables CPU to communicate with RTC. The boot loader then boots the program again.

• WAKEUP logic REQUIRES writing a 1 to RTC Interrupt Flag Register, before a subsequent wakeup event (pulse) can wake-up the system.

– Clear EXTFL bit of RTC Interrupt Flag Register (bit 5 of RTCINTFL - 0x1920) by writing a 1 after a WAKEUP event to detect future WAKEUP events

同问帖子: www.deyisupport.com/.../172594.aspx