Calling Serial.end() on STM32L073RZTx results in high power consumption

[CropWatchDevelopment]

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Describe the bug
After calling begin() on HardwareSerial ports, running end() does not fully stop, and clean up the serial port.

Steps to reproduce the behavior:
Flash first code example, see a power useage of 25uA
Flash 2nd code sample, see power usepage of ~300uA

Expected behavior
The 1st example's current consumption should equal that of the 2nd

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Linux Mint
• IDE version: PlatformIO
• Upload method: [e.g. SWD] STLINK v2's SWD

Hardware (please complete the following information):

• Board Name: STM32L073RZTx
• Extra hardware used if any: PowerProfiler 2

Additional context
Add any other context about the problem here.

Code example 1, Power consumption ~25uA:

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

// Create HardwareSerial objects
HardwareSerial Serial1(USART1);
HardwareSerial Serial2(USART2);
HardwareSerial Serial4(USART4);

void setup()
{
  // // Initialize serial ports for a short period
  // Serial2.begin(115200);
  // Serial1.begin(9600);
  // Serial4.begin(9600);

  // // // End the serial ports
  // Serial2.end();
  // Serial1.end();
  // Serial4.end();

  LowPower.begin();
  LowPower.deepSleep(20000);
}

void loop()
{
  // Nothing to do here
}

Code Example 2, Calls both Begin() and End() however, this example runs at ~500uA:

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

// Create HardwareSerial objects
HardwareSerial Serial1(USART1);
HardwareSerial Serial2(USART2);
HardwareSerial Serial4(USART4);

void setup()
{
  // Initialize serial ports for a short period
  Serial2.begin(115200);
  Serial1.begin(9600);
  Serial4.begin(9600);

  // // End the serial ports
  Serial2.end();
  Serial1.end();
  Serial4.end();

  LowPower.begin();
  LowPower.deepSleep(20000);
}

void loop()
{
  // Nothing to do here
}

FINALLY,
running this example rund at around 1mA:

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

// Create HardwareSerial objects
HardwareSerial Serial1(USART1);
HardwareSerial Serial2(USART2);
HardwareSerial Serial4(USART4);

void setup()
{
  // Initialize serial ports for a short period
  Serial2.begin(115200);
  Serial1.begin(9600);
  Serial4.begin(9600);

  // // // End the serial ports
  // Serial2.end();
  // Serial1.end();
  // Serial4.end();

  LowPower.begin();
  LowPower.deepSleep(20000);
}

void loop()
{
  // Nothing to do here
}

[fpistm]

Hi @CropWatchDevelopment
This is normal as when you call end only the USART RCC are disabled.
Anyway the pins used by the Serial still configured mainly the GPIO clock, it could not be disabled because it do not know if another pins on the same GPIO port are used or not.
So it is up to the application to disabled those clocks.

[fpistm]

Hi @CropWatchDevelopment
I've made a test with a Nucleo L053.
Here my result with this sketch:

#include "STM32LowPower.h"

// Create HardwareSerial objects
HardwareSerial Serial1(USART1);
HardwareSerial Seriallp1(LPUART1);

void setup() {
  // Initialize serial ports for a short period
  Serial.begin(115200);
  Serial1.begin(9600);
  Seriallp1.begin(9600);

  // // End the serial ports
  Serial.end();
  Serial1.end();
  Seriallp1.end();
  __HAL_RCC_GPIOA_CLK_DISABLE();
  __HAL_RCC_GPIOB_CLK_DISABLE();
  __HAL_RCC_GPIOC_CLK_DISABLE();

  LowPower.begin();
}

void loop() {
  delay(2000);
  LowPower.deepSleep(2000);
}

When in deepSleep, average is 6.3µA:

If I remove the __HAL_RCC_GPIO*_CLK_DISABLE, average is 6.8µA. As you can see gain in really low.
With the Nucleo L053, I have not 3 USART but 2 USART and 1 LPUART which consumes less than the USART, anyway it does not explain your result.
In fact ti depends on your board, where you measure and also which oscillator you used HSE, HSI, HSI48 enabled or not.
Nucleo L053 uses an HSE bypass and nothing else. As I've measured at the IDD, it is not measured.
Nucleo L073 enables the HSI and HSI48 by default and it is measured at the IDD.

The Serial.end() works as expected. So I close this issue.