NEC Release-it, Hardware Manual

Page: 17 / 30

UM U17586EE1V0UM00 17
CHAPTER 3
POWER SUPPLY
There are two choices to supply power to the board, USB or a 006P battery via CN2. Please refer to
2.1.3 JP1 for the jumper setting.
Please replace the battery with a new one, if the voltage level goes down to 6.5V.
Below the voltage level of 6.5V, functions of the board are not guaranteed.
The battery voltage can be checked at the port P20 as shown below.
Battery Check
Name MCU Pin Description
BT_MONI P20/ANI0 33.8% of the battery output is available at
ANI0.
For instance, if the battery level is 9 V,
the level of the BT_MONI = 0.338×9.0 V
=
3.042 V
If the battery level is 6.5 V, the level of the
BT_MONI = 0.338×6.5 V = 2.197 V