Xác định công việc bởi vì họ trực tiếp sao chép trong chuỗi và cho phép lắp ráp đánh giá nó. Điều này là khác nhau từ tương đương, đánh giá một chuỗi và lưu trữ nó như là một hằng số tham chiếu đến nhãn. Điều này có thể gây ra một số khác biệt tinh tế có thể là một vấn đề nếu bạn không biết những gì bạn đang làm. Ví dụ, nếu bạn đã có mã | Simpo PDF Merge and Split Unregistered Version - http Get154Table retlw 0X0E0 retlw 0X0D0 retlw 0X0B0 retlw 0X070 Minutes 0 15 Minutes 16 31 Minutes 32 47 Minutes 48 59 This code takes a maximum of 34 instruction cycles to execute. This code with the code presented above means that the vast majority of time the PIC microcontroller spends processing in this application is spent polling the T0IF flag instead of calculating the new LED s display value. This is important to avoid any possibility that the T0IF flag being set is missed and the time is lost . xmas CHRISTMAS DECORATION WITH BLINKING LIGHT AND MUSIC If you look through the hobbyist electronics magazines in December you are sure to find a number of flashing-light PIC microcontroller applications. These applications usually use a number of LEDs to flash on and off in a seemingly random pattern. These lights are often put in a Christmas tree decorations or a stand-alone decoration as shown in the X mas project Fig. which has 15 flashing LEDs and can play a tune. This is the third time I ve created a lighted Christmas tree with a PIC microcontroller. In the first case I hand-wired all the connections which made it truly horrific to wire . Figure The Christmas tree decoration with stickers for ornaments. Simpo PDFj Merge and Split Unregistered Version - http The second version used a predesigned PCB card but the design was lost in a hard file crash before I started religiously backing up files onto CD-ROM and the software was written for an early PIC microcontroller compiler that never worked extremely well. I ended up updating it just for the light application and the tune generator that went with it . Also with the second version I created an unnecessarily complex tune generator that requires two separate PC applications to run before the code could be built with the tune installed. This third version avoids the problems of the other two and by using LEDs with .