Research And Design Of Real Time Clock Chip With Frequency Self-Calibrating

Real Time Clock (RTC) is a special integrate circuit with high density integration.The main function of RTC is to preserve track time and date. The RTC has been widelyused in consume electronics, where low power and high accuracy count is required.Nowadays,Quartz oscillators provide an accuracy far superior to other conventionaloscillator designs. Nevertheless, the temperature plays a key role on Quartz oscillatoraccuracy. Therefore, adjusting the RTC based on the temperature characteristic isabsolutely necessary.Since the temperature has a great impact on oscillator frequency,this thesisproposes a real time clock chip base on 3-wire SPI (Serial Peripheral Interface) and acalibration algorithm. The chip integrates RTC and Temperature Sensor. Morespecifically, the RTC uses the interrupt function to control temperature sensor. Thetemperature information is collected by the sensor and then translated to digital signal byADC (Analogue Digital Converter). The control logic employs the signal to look up theSRAM table and then adjusts the calibration register. Thus, the RTC adjusts the frequencydynamically to meet the changes of temperature.This design is carried out based on Top-Down method. The RTL level of the chipis implemented by Verilog-HDL,the physics design is accomplished by Synopsys tools.The main blocks and software architecture are discussed.