Currently meeting with a question about sleep wake up, totally have no idea, refer to the great god
Background: at present is to develop test uno board, because behind intends to use the battery power, so he thought of using energy saving sleep mode; Use bluetooth module JDY - 16, read and write using 0, 1 two pins; Bluetooth library using SoftwareSerial, sleep use Enerlib library energy. The PowerDown () method,

After enter power down mode, program did stop running, but the bluetooth module is still running, this is normal?
Then see the information on the said power lost mode only interrupts can wake up, but I will break statement annotations, use their phones to send information to the bluetooth, bluetooth after receiving the signal will be aroused, uno directly take over information and wake up after reading what all didn't read,
Why in the received signal will be awakened directly?