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Increased consumption in low power modes

Monika KUNCOVA
Visitor II
Power consumption in low power mode is higher than expected. Problem remains after reset, but is solved by power cycling the MCU. What is the problem?Issue can be caused by debug in low power mode option. When developers debug their code in low-power mode,they use debug in low-power option. It can be enabled by using an option in IDE or manually by setting register bits. Those bits are located in Debug MCU configuration register (DBG_CR).
Debug MCU configuration register (DBG_CR):
857.png
Register contains 3 bits
  • DBG_STANDBY: Debug Standby mode
  • DBG_STOP: Debug Stop mode
  • DBG_SLEEP: Debug Sleep mode

When some of these bits are active, the debug module and some of the internal clocks are active during low-power mode and this causes increased power consumption.
When developers reset or reprogram MCU with release version of firmware they still remain active if the MCU didn’t go through power reset.
Register is reset only during power-on reset (POR). Thus, issue can be solved by manually clearing debug bits in DBG_CR or reset using power cycling of MCU.
 
Version history
Last update:
‎2020-11-09 12:23 AM
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