1 00:00:03,460 --> 00:00:03,880 Hello. 2 00:00:04,090 --> 00:00:11,140 So in this final section we are going to talk about how to create interrupt without timers. 3 00:00:11,320 --> 00:00:20,280 So I should point out we are creating an entirely new cookbook series for interrupt on the call text. 4 00:00:20,320 --> 00:00:27,630 And with that cookbook series we are going to give a detailed explanation tutorial for interrupt to 5 00:00:27,640 --> 00:00:35,170 what we are going to do here and this cause is a very very short summary of interrupt. 6 00:00:35,190 --> 00:00:42,790 What time is I don't by any means expect you two to understand the intricacies of interrupt from this 7 00:00:42,790 --> 00:00:50,100 lesson but it's just a short course a short tutorial to show you how to create timer interrupt. 8 00:00:50,140 --> 00:00:55,710 So before we start I'll just give you an overview of interrupts for people who don't know what interrupt. 9 00:00:56,590 --> 00:01:01,740 So over here we have a picture of a person waiting for the phone to ring. 10 00:01:01,990 --> 00:01:03,000 Right. 11 00:01:03,070 --> 00:01:09,300 Interrupt versus pull in so a single microprocessor can save several devices. 12 00:01:09,300 --> 00:01:12,790 As we know that and yet two ways to do that. 13 00:01:12,790 --> 00:01:20,680 You can use interrupt or you can use pull in in the interrupt method whenever any a device needs a service 14 00:01:21,090 --> 00:01:28,540 that device notifies the CPA you by sending it an interrupt signal upon receiving an interrupt signal 15 00:01:28,580 --> 00:01:36,730 to see you interrupt whatever it is doing says the device the program associated with it interrupt is 16 00:01:36,740 --> 00:01:42,200 called the interrupt service routine or the interrupt handler in Poland. 17 00:01:42,250 --> 00:01:49,350 The CPSU continuously monitors the stages of a given device when the status condition is met. 18 00:01:49,360 --> 00:01:51,700 It performs the service. 19 00:01:51,730 --> 00:01:57,230 After that it moves on to monitor the next device until each one is serviced. 20 00:01:58,180 --> 00:02:02,640 So look at this bunch here waiting for the phone to ring. 21 00:02:02,770 --> 00:02:06,830 You can take this man as the CPSU right. 22 00:02:06,850 --> 00:02:09,490 How do we operate in our daily lives. 23 00:02:09,520 --> 00:02:17,260 We go about our lives read a book watch a movie or do whatever you doing when the phone rings. 24 00:02:17,320 --> 00:02:22,630 Then you pick up the phone to ring tone of the phone is the interrupt signal. 25 00:02:22,630 --> 00:02:23,200 Right. 26 00:02:23,230 --> 00:02:28,360 But in this picture we have a person sitting and waiting for the phone. 27 00:02:28,380 --> 00:02:31,040 A person looking at a phone to ring. 28 00:02:31,150 --> 00:02:32,880 This is Poland right. 29 00:02:33,400 --> 00:02:39,770 This man is practically pulling the phone to ring rather than going about his daily life. 30 00:02:39,820 --> 00:02:43,450 Wait until he had to rent one and then pick up the phone. 31 00:02:43,540 --> 00:02:43,810 Right. 32 00:02:43,810 --> 00:02:51,970 So that is the difference between interrupt and pull in and which polling a lot of CPSU is wasted because 33 00:02:51,970 --> 00:02:57,810 the CPE would always have to check and monitor the status of a given device. 34 00:02:57,880 --> 00:03:04,930 And if you have many devices the CBI has to monitor each and every one of them and see what the condition 35 00:03:04,930 --> 00:03:12,670 is met or not met whereas Yeah the resources that particular CPE resources could be put to better use. 36 00:03:12,760 --> 00:03:15,370 So this is where interrupt comes in. 37 00:03:15,370 --> 00:03:23,770 And often we implement polling by using if statement like if a is less than beat and do this if it is 38 00:03:23,770 --> 00:03:33,100 greater than this if pin B is high or if this or if that's often performed poorly in this way. 39 00:03:33,520 --> 00:03:42,340 So we'll go ahead and go to you vision and write our interrupt program and create to interrupt service 40 00:03:42,340 --> 00:03:49,220 routines and let the let the program run automatically whenever they interrupt Cass.