From fb18705b9b9cc10e15e56cea6697839f3779bdb6 Mon Sep 17 00:00:00 2001 From: Daniel Thompson Date: Fri, 4 Jun 2021 10:49:33 +0100 Subject: [PATCH] manager/rtc: Experimental power saving technique Currently the time is calculated 8 times per second from (relatively) slow python code. Optimize the power consumed by reducing the number of times we check for wall time updates to only once-per-second and use native code generation to reduce VM overhead when executing this critical code. At the time of writing the difference is battery life has not yet been measured (but we know the current master branch is worse than v0.4 and, in theory at least, this should close the gap). Signed-off-by: Daniel Thompson --- wasp/drivers/nrf_rtc.py | 6 +++++- wasp/wasp.py | 1 + 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/wasp/drivers/nrf_rtc.py b/wasp/drivers/nrf_rtc.py index 100bacd..e68b957 100644 --- a/wasp/drivers/nrf_rtc.py +++ b/wasp/drivers/nrf_rtc.py @@ -45,6 +45,7 @@ class RTC(object): self._uptime = 0 self.set_localtime((2020, 3, 1, 3, 0, 0, 0, 0)) + @micropython.native def update(self): """Check for counter updates. @@ -59,10 +60,12 @@ class RTC(object): self.lastcount += split self.lastcount &= (1 << 24) - 1 + uptime = self._uptime self._uptime += split machine.mem32[0x200039c8] = self._uptime * 125 - return True + # Has the seconds count changed + return bool((self._uptime ^ uptime) & 0x08) def set_localtime(self, t): """Set the current wall time. @@ -103,6 +106,7 @@ class RTC(object): localtime = self.get_localtime() return localtime[3:6] + @micropython.native def time(self): """Get time in the same format as time.time""" return self.offset + (self._uptime >> 3) diff --git a/wasp/wasp.py b/wasp/wasp.py index 6c3e4ef..eaf3737 100644 --- a/wasp/wasp.py +++ b/wasp/wasp.py @@ -430,6 +430,7 @@ class Manager(): watch.touch.reset_touch_data() + @micropython.native def _tick(self): """Handle the system tick.