tailieunhanh - Úng dụng ví dụ

Một số ví dụ ứng dụng MSP430 được đưa ra trong các phần sau đây. Phổ biến gần như tất cả trong số họ là lưu trữ dữ liệu hiệu chuẩn, các bảng biểu, hằng số, trong EEPROMs bên ngoài. EEPROMs bên ngoài được sử dụng cho lý do an toàn. Nếu máy vi tính không hoàn toàn, nó vẫn còn tương đối dễ dàng để đọc ra các giá trị tiêu thụ tích lũy. Điều này thường là không thể nếu các giá trị này cư trú trong EEPROMs nội bộ. Những EEPROMs này cũng có thể lưu trữ các bảng mô tả các lỗi. | Chapter 4 Application Examples Several MSP430 application examples are given in the following sections. Common to nearly all of them is the storage of calibration data tables constants etc. in the external EEPROMs. External EEPROMs are used for safety reasons. If the microcomputer fails completely it is still relatively easy to read out the accumulated consumption values. This is usually impossible if these values reside in internal EEPROMs. These EEPROMs can also store tables that describe the principal errors of a given measurement principle that is dependent on the input value current flow heat etc. . The MSP430 with its excellent table processing capabilities can determine the right starting value out of these tables and calculate the linear quadratic or cubic approximation value. The following figure shows the principal error of a meter. The complete range starting at 1 up to 200 is divided into sub ranges of different length. A stored table would contain the starting point the different distances and the inherent error at the beginning of each range. With this information the MSP430 can calculate the error at any point of the measurement range. 4-1 Electricity Meters Overview The MSP430 can be used in two completely different kinds of electronic electricity meters. The difference between the two methods is mainly where the electrical energy W Ị U X I X dt is measured The electrical energy is measured in a front-end separated from the MSP430. Several methods exist for doing that Hall effect sensors Ferraris wheel pick-ups analog multipliers etc. The interface to the MSP430 is normally a train of pulses where every pulse represents a defined amount of energy Ws kWs Wh . All family members can be used for this purpose. The electrical energy is calculated by the MSP430 itself using its 14-bit analog-to-digital converter ADC for the measurement of current and voltage. Only the MSP430C32x can be used for this purpose. The two different methods are shown .