AN2000 VIPower：VIPer53双输出的参考电路板90到264 VAC输入，24W输出

AN2000 VIPower：VIPer53双输出的参考电路板90到264 VAC输入，24W输出

AN1572
APPLICATION NOTE

Power Loss Time-Stamp Function

INTRODUCTION
Applications often require the ability to time-stamp when the main power was lost. This can allow the sys-
tem, after it powers back up, to determine whether certain scheduled activities or events may have been
missed as a result of the power loss. STMicroelectronics has developed a family of RTCs which handle
this time-stamping function automatically (see Table 2., page 2).




HALT UPDATE BIT OPERATION
During normal operation, the real-time clock contents are periodically transferred to the TIMEKEEPER
Registers. The system reads/wr