From: wangmengyang <wangmengyang@espressif.com>
Date: Tue, 9 Apr 2019 09:06:16 +0000 (+0800)
Subject: reduce the minimum delay uncertainty of esp_timer for Bluetooth modem sleep from... 
X-Git-Tag: v4.0-beta1~293^2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=f678a6289db21b7a6841dac779a6b076cbc8d3ca;p=esp-idf

reduce the minimum delay uncertainty of esp_timer for Bluetooth modem sleep from 1.8ms to 0.5ms for lower power consumption
---

diff --git a/components/bt/bt.c b/components/bt/bt.c
index a4e813cf9b..96f968bc08 100644
--- a/components/bt/bt.c
+++ b/components/bt/bt.c
@@ -818,7 +818,7 @@ static void btdm_sleep_enter_phase1_wrapper(uint32_t lpcycles)
     // start a timer to wake up and acquire the pm_lock before modem_sleep awakes
     uint32_t us_to_sleep = btdm_lpcycles_2_us(lpcycles);
 
-#define BTDM_MIN_TIMER_UNCERTAINTY_US      (1800)
+#define BTDM_MIN_TIMER_UNCERTAINTY_US      (500)
     assert(us_to_sleep > BTDM_MIN_TIMER_UNCERTAINTY_US);
     // allow a maximum time uncertainty to be about 488ppm(1/2048) at least as clock drift
     // and set the timer in advance