POWER_SAVING打开时，CC2541无法广播

POWER_SAVING打开时，CC2541无法广播CC2541。sniffer抓取不到任何数据。

目前我的ＢＬＥ板子没有设计触发按键，所以需要蓝牙一直工作在低功耗广播状态下。我打算采取的方案是１Ｓ广播一次，400MS的任务定时。在没有广播或任务时，需要蓝牙进入低功耗P2模式。

这个是adveritise 设置

static uint8 advertData[] =
{
// Flags; this sets the device to use limited discoverable
// mode (advertises for 30 seconds at a time) instead of general
// discoverable mode (advertises indefinitely)
0x02, // length of this data
GAP_ADTYPE_FLAGS,
DEFAULT_DISCOVERABLE_MODE | GAP_ADTYPE_FLAGS_BREDR_NOT_SUPPORTED,

// service UUID, to notify central devices what services are included
// in this peripheral
0x03, // length of this data
GAP_ADTYPE_16BIT_MORE, // some of the UUID's, but not all
LO_UINT16( SIMPLEPROFILE_SERV_UUID ),
HI_UINT16( SIMPLEPROFILE_SERV_UUID ),

};

广播间隔是1S（1600）时sniffer可以偶尔收到数据包，但是大部分都是FCS错误（见附图）。200MS时完全收不到数据包。

电路板上没有设计外部 32.768H晶振， 在另外的论坛上搜到的相关解释：

问：

I had a project that worked just fine with the default power management settings.

Once I turned on the POWER_SAVING flag, the device started getting stuck when sleeping from the main loop.

Specifically, This behavior is presented in void halSleep( uint32 osal_timeout ) in hal_sleep.c, in line 344:

// check if radio allows sleep, and if so, preps system for shutdown
if ( LL_PowerOffReq(halPwrMgtMode) == LL_SLEEP_REQUEST_ALLOWED )

When stepping over the call to LL_PowerOffReq, the debugger stops responding and the device probably does too, for no good reason. When manually pressing the "break" button in the workbench, I reach llStopTimer2(), but never leaves there.

I can't step-in to the function because it has no source. When stepping through the assembly it's difficult to determine when exactly it gets stuck, since it does all sorts of banked-code trickery, various jumps etc, and the debugger responds VERY slowly to single-instruction stepping (don't understand why).

This happens right on the first sleep the device encounters. I'm working without any optimizations. Using CC-Debugger.

Any help will be appreciated.

答复：

Do you have an external 32.768Hz oscillator?

LLPowerOffReq doesn't really do anything interesting apart from stopping the MAC timer and syncing it with the sleep timer. Which will require a functional sleep timer.

没有32Khz外部晶振，不能进入sleep状态么？

没有回？还是自己顶吧。问题解决了。32Ｋｈｚ晶振必须焊上才能进入低功耗休眠状态（ＰＭ２）。无广播时电池电流约１５０ｕＡ。

但是有个疑问，没有３２Ｋｈｚ晶振，系统自带的ＲＣ振荡器（３２Ｋ）不能工作么？希望有大神来解释。

没有外部32KHz晶振也可以进入PM2的，需要修改main里的HAL_BOARD_INIT()这个宏。把切换到外部32KHz晶振的代码删掉即可,相关引脚也要做处理。

/* Board Initialization */
#define HAL_BOARD_INIT()                                                       \
{                                                                              \
  /* Set to 16Mhz to set 32kHz OSC, then back to 32MHz */                      \
  START_HSOSC_XOSC();                                                          \
  /*SET_OSC_TO_HSOSC(); 使用内部32K时钟*/                                                         \
  /*SET_32KHZ_OSC();*/                                                             \
  SET_OSC_TO_XOSC();                                                           \
  STOP_HSOSC();                                                                \
                                                                               \
  /* Enable cache prefetch mode. */                                            \
  PREFETCH_ENABLE();                                                           \
}

楼上正解，已标记为正确答案

/* Sleep Clock */

#define EXTERNAL_CRYSTAL_OSC 0x80 //0x00 // external 32kHz XOSC
#define INTERNAL_RC_OSC 0x80 // internal 32kHz RCOSC

这个可以定义使用外部还是内部32.768晶振……