Serial is not output normally when returning from DeepSleep

[nopnop2002]

Serial is not output normally when returning from DeepSleep

My Envitonment

STM32F103(8MHz Xtal) + platformIO

Platform Manager
================
Platform ststm32
--------
Checking platformio/ststm32                   15.2.0                             [Up-to-date]
Checking platformio/toolchain-gccarmnoneeabi  1.70201.0 @ >=1.60301.0,<1.80000.0 [Up-to-date]
Checking platformio/framework-arduinoststm32  4.20100.211028 @ ~4.20100.0        [Up-to-date]
Checking platformio/framework-arduinoststm32-maple 3.10000.201129 @ ~3.10000.0        [Up-to-date]
Checking platformio/tool-stm32duino           1.0.1 @ ~1.0.1                     [Up-to-date]
Checking platformio/tool-openocd              2.1100.211028 @ ~2.1100.0          [Up-to-date]
Checking platformio/tool-dfuutil              1.9.200310 @ ~1.9.190708           [Up-to-date]

My config

[platformio]
default_envs = blackpill_f103c8

[env:blackpill_f103c8]
platform = ststm32
board = blackpill_f103c8
framework = arduino
lib_deps =
  https://github.com/stm32duino/STM32LowPower
  https://github.com/stm32duino/STM32RTC

My code

#include <Arduino.h>
#include "STM32LowPower.h"

void setup() {
  LowPower.begin();
  Serial.begin(115200);
  Serial.println("serial (same as 1)");
  Serial.println("*****");
}

void loop() {
  Serial.println("serial printing");
  for(int i=0;i<20;i++) LowPower.deepSleep(1000);
  //for(int i=0;i<20;i++) LowPower.sleep(1000);
  //for(int i=0;i<20;i++) LowPower.idle(1000);
  //delay(1000);
}

Problem

Serial is not output normally when returning from DeepSleep.

Serial is output normally when returning from Sleep.

Serial is output normally when returning from Idle.

Screen Shot

[fpistm]

Same here than #68. Use Serial.flush(). Entering and exiting sleep mode change the clock that's why you probably seen this.

[nopnop2002]

Good!! It's solved.

void loop() {
  //unsigned long nowMillis = millis();
  //Serial.println(nowMillis);
  Serial.println("serial printing");
  Serial.flush();
  for(int i=0;i<20;i++) LowPower.deepSleep(1000);
  //for(int i=0;i<10;i++) LowPower.sleep(1000);
  //for(int i=0;i<5;i++) LowPower.idle(1000);
  //delay(1000);
}