DS1302 is a trickle charge clock IC
launched by DALLAS company, USA. RAM 31 bytes adopts synchronous communication with CPU by SPI three line interface, automatic adjustment when less than 31 days in one month and leap year compensation function. Operation voltage: 2.5 - 5V, TTL voltage compatible, dual power supply.
There are following disadvantages about DS1302:
It has low clock precision; It is easy to be affected by the environment and have clock disorders etc.
DS1302 can be used for data recording, especially for certain data points with special significance. The data can be recorded with the time when the data appears. There are great significance about this kind of record for the results analysis of the continuous measurement and control system and the cause finding of abnormal data. Traditional data recording are interval sampling or timing sampling, but without specific time record. Therefore, data can only be recorded but can not accurately record the time when the data occurred. If timing by single chip microcomputer, on the one hand, you need counter, so it will take up hardware resources; On the other hand, you also need to set the interrupt, queries, etc., it also will cost the single chip microcomputer resource. Moreover, some measurement and control system may not allow to do so. However, if the clock chip DS1302 is used in the system, this problem can be solved very well.
WT8302: WT8302 can be used directly instead of 1302.
Features: 240 byte, static RAM, operation voltage: 2.6V- 6V, programmable alarm clock, timing and interrupt function. The power consumption is much lower. The maximum operation current 200uA at Vcc=3.0V, 32.768Khz or 50Hz can be selected. There is bulit-in base source with 32.768Khz. All in all, it is more accurate and stable than 1302. By two lines serial port, so it can save the MCU interface. In WT8593, bulit-in 32.768KHZ high precision clock source. Ultra low power consumption only needs 200uA. By dual-line bus, so the MCU interface resources can be saved (1302 needs three lines), and it is not easily affected by the environment.