Method and device for monitoring rtc chip power down and crystal oscillator stop vibration

Abstract

The invention discloses a method and device for monitoring RTC chip power-off and crystal oscillator stop vibration, relates to the technical field of clock circuit detection, and improves the working efficiency of maintenance equipment. The main technical solution of the invention is: a device for recording data at power-off time , including: an MCU chip, an RTC chip, a power supply battery, a first capacitor, a second capacitor and a power supply conversion circuit; the MCU chip is connected to the RTC chip; the power supply battery and the first capacitor are connected in parallel to the RTC Between the standby power pin of the chip and the ground; the power supply conversion circuit includes a switch control terminal, a first switch switch terminal and a second switch switch terminal; the switch control terminal is connected to the positive pole of the power supply battery and the voltage dividing resistor respectively connected, the other end of the voltage dividing resistor is grounded; the first switch switch terminal is connected to the main power pin of the MCU chip and the RTC chip respectively, and the second switch switch terminal is connected to the second capacitor connected in series with ground. The invention is used for monitoring RTC chip power down and crystal oscillator stop vibration.

Description

technical field [0001] The invention relates to the technical field of clock circuit detection, in particular to a method and a device for monitoring the power failure of an RTC chip and the stop of a crystal oscillator. Background technique [0002] Real Time Clock (RTC) is usually called a clock chip, which can provide people with accurate real-time time, can time the year, month, day, hour, minute and second, and has various functions such as leap year compensation. Alternatively, a precise time reference can be provided for the electronic system. [0003] At present, most RTC chips use crystal oscillators with high precision as the clock source. In order to realize the power-down protection when the main power fails, so that the RTC chip can continue to work normally, it is necessary to connect an external backup battery in the integrated circuit to ensure Continuously supply power to the RTC chip. [0004] However, when the voltage of the backup battery drops or the v...

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Problems solved by technology

[0004] However, when the voltage of the backup battery drops or the voltage of the backup battery drops suddenly due to other external reasons, the crystal oscillation conditions will change accordingly, which cannot satisfy the normal operation of the RTC chip, and the RTC chip will stop timing. The voltage drop of the battery or the voltage drop of the backup battery due to other external reasons will eventually cause the crystal oscillator to stop vibrating, causing all the time data recorded in the RTC chip to be lost. Then when the device with the RTC chip is powered on again, the RTC chip will The data read in is the default initial value, that is, the time data recorded in the RTC chip is reset. The existing processing method is often to return the device with the RTC chip to reset the time, especially for the closed time reset function. The equipment can only take such countermeasures. It not only consumes a lot of equipment maintenance costs, but also causes the life cycle of the equipment to end prematurely due to the frequent return of time, reducing the service life of the equipment.

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