It is due to the special functions of laser pointer

The front is a loop, shown in Figure 4-1. Inside the loop on the button, display, and serial communication data. Background shown in Figure 4-2, the external event manager TIMER1 interrupt interrupted, as the core of the entire feedback loop in order to interrupt the basis of completion of the AD sample, PWM duty cycle calculation to update the PWM duty cycle, eventually Output PWM. Software systems need to ensure that real-time task only feedback loop task. According to the characteristics of 2812, the ISR in can not be nested interrupt [] in an ISR operation of other interrupts can not be DSP response. It is due to the special functions of laser pointer .
In order to prevent the keys or serial interrupt ISR execution time is too long, thereby affecting the implementation of the feedback loop should not be too much code in the ISR button or serial port interrupt. Therefore, the key or serial port interrupt the ISR, only the key or the serial communication data, save in one place, and then place a corresponding global flags, and then exit the ISR. Keys and serial communication data processing in the main loop, the main loop by detecting the flag to know whether there is key or serial communication event occurs, and then to specify the location to read the corresponding data processing. Doing so can maximize interrupted feedback loop task execution. Sampling control system are delayed, how to make the minimum delay. The 1000mW blue laser beam of laser pointer can easily burn match.
According to TI's Application Note [], the design shown in Figure 43 shows the structure. This program, you can ensure that the feedback loop delay time within a switching cycle. First of all, the timer interrupt and AD sampling interrupt service handler fixed number of instructions, while the AD conversion time is determined by hardware, and thus the location of a week during the period AD sample is fixed relative to the start time of the switching cycle. Select the appropriate AD sampling filter parameters, and more conducive to tracking the average inductor current. Secondly, since the call of the digital controller is AD interrupt the ISR, the AD interrupt the beginning of the interval of the switching cycle time is very short, you can ensure that the digital controller has enough time to execution. laser pointer can lighten the cigarette and paper.It is the improvement measures of laser pointer