OLIMEX© 2015
STM32-P405 user's manual
from an external battery, an external supercapacitor, or from VDD when no external battery nor an
external supercapacitor are present. VBAT operation is activated when VDD is not present. The VBAT
pin supplies the RTC, the backup registers and the backup SRAM.
The board consumes around 0.25W (e.g. 0.04A at 6V) with both LEDs on. You can enable one of the low-
power modes to reduce the consumption.
By default, if you have successfully powered the board its PWR LED would turn on. The STAT LED
would blink 10 times. In case you you have modified the software (or if you have changed the positions
of the jumpers responsible for the boot location) the STAT LED might not turn on at all since it is
initialized by the code loaded on the flash memory of the board.
The red LED should always turn on upon powering. Note that it is possible to have the PWR LED on
even if there isn't enough power for proper operation of the board and all the peripherals currently
connected.
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