bạn nhìn thấy mà theo nhà nước waitUA, đầu vào của tín hiệu DLCstopped là mất tích. Sửa lỗi Bạn sẽ thêm đầu vào bị mất tín hiệu DLCstopped theo nhà nước waitUA trong quá trình công văn. A. Khi mô phỏng đang chạy, biên tập ngăn cản bạn từ việc thay đổi mô hình SDL: thoát ra từ các | Quick Tutorial on SDL 15 Figure Start transition Figure shows an example of start transition n is set to 0 signal SABME is transmitted and timer T607 is started before going to state disc. States States must be defined using a state symbol. A common mistake is to confuse the notions of state and nextstate Figure is incorrect because state disc is not defined Figure is correct because state disc is defined. Figure State disc defined When the character - is entered in a nextstate as in Figure it means that after executing the transition the state will remain unchanged. process process1_1 V76frame xlz - Figure Dash nextstate Input Signals reaching a process instance are stored into its FIFO queue. When performing an input the first signal in the queue the oldest one is removed from the queue and the values of the signal parameters if any are assigned to the variables specified in the input symbol. 16 Validation of Communications Systems with SDL Note that if the first signal in the queue is not present in any input below the current process state the signal will be discarded lost . This is called an implicit transition. In Figure left part the FIFO queue of process display contains the signals blue green and red. Process display being in state idle the signal blue is discarded lost and then green is input leading to state resizing. Signal red is now first in the queue. block b2 block b2 red y green V blue sr1 chi process display idle resizing V red display sri display chi red red blue blue _ green _ state idle green Figure The FIFO queue of one instance of process display state resizing Save To avoid losing signal blue as in Figure we add a save symbol below state idle as depicted in Figure . When a signal is saved it stays in the input queue at the same position and the next signals in the queue are examined to see if they can be input saved or discarded. action input green input blue etc. Figure
