Microprocessor based taxi fare meter - has voltage sensor to ensure min. power consumption, except when information is being processed

摘要

A microprocessor is used as the basis of a taxi fare meter. The system is designed for power consumption only when information is being processed, except for memory units. The microprocessor(1) operates to a programme held in an ROM. An additional CMOS direct access memory(2) contains all details of tariffs and a display unit(3) is used for relevant information. A clock generator(4) together with frequency divider (5) provides the system time base. The main vehicle battery(6) is backed by an auxiliary(7) that operates over voltage sensing logic(11). The sensing stage ensures that the minimum power is consumed for data storage.