1 00:00:02,700 --> 00:00:03,420 Hello fellas. 2 00:00:03,450 --> 00:00:04,230 Welcome back. 3 00:00:04,230 --> 00:00:12,000 So in this third lesson of the ATC section we're going to look at how to use timers to trigger ATC conversions 4 00:00:12,290 --> 00:00:14,610 Lenton all time as in the previous section. 5 00:00:14,730 --> 00:00:21,890 So I think there's the right time to combine time is an 86 to make really good applications and using 6 00:00:21,930 --> 00:00:28,410 time to trigger ATC conversion becomes very important when you are doing something that requires precise 7 00:00:28,500 --> 00:00:29,460 sampling. 8 00:00:29,460 --> 00:00:35,290 You can actually set a timer to request the conversion from the ATC based on the period you set. 9 00:00:35,300 --> 00:00:40,550 So if you don't understand what I just said don't worry we are going to demonstrate that now. 10 00:00:40,570 --> 00:00:43,550 So let's go to Cuba mix and create our new project. 11 00:00:43,560 --> 00:00:45,450 This is the old project where we left off. 12 00:00:45,480 --> 00:00:48,110 I'll just come to my Cuba makes is right over here. 13 00:00:49,770 --> 00:00:58,030 And I'm just going to close this and I'm going to minimize this and come to file new when I select my 14 00:00:58,030 --> 00:01:06,770 board and my board is disco board and it's an F4 and it's this one over here 15 00:01:09,910 --> 00:01:12,170 what I want is of course Claire opens 16 00:01:14,980 --> 00:01:21,080 and like we're doing in this section my ATC channel is the ATC autonomous view which is connected to 17 00:01:21,080 --> 00:01:28,040 my PSU and this in this particular lesson we want to additionally initialize a time to work with it. 18 00:01:28,400 --> 00:01:34,220 So let's just use time to provide a clock source using the internal clock as the clock source for time 19 00:01:34,220 --> 00:01:35,140 or two. 20 00:01:35,150 --> 00:01:41,270 So once this is done we can go to the configurations top to continue configuration click over here and 21 00:01:41,270 --> 00:01:47,090 then I start with the ATC and what I'm going to do is I'm just going to leave the resolution the same 22 00:01:47,540 --> 00:01:56,000 and I'll come over here ATC regular conversion this under the section now select external trigger conversion 23 00:01:56,000 --> 00:02:02,450 source and this is where I select my timer and like we chose over there we chose time of two and we 24 00:02:02,450 --> 00:02:07,010 use it use in the out event that's the default. 25 00:02:07,130 --> 00:02:09,450 So we're using time to alter event. 26 00:02:09,740 --> 00:02:16,400 And like we realized before we realized keeping the default three cycles makes the thing free. 27 00:02:16,460 --> 00:02:20,210 So let's just choose fairly normal cycle. 28 00:02:20,270 --> 00:02:23,970 This is 56 cycle for sampling time so fifty six plus twelve. 29 00:02:24,140 --> 00:02:28,680 I just do something less I'll choose eighty four cycles here. 30 00:02:28,770 --> 00:02:29,090 Right. 31 00:02:29,090 --> 00:02:37,490 Moving on so the only in we've made just to recap we kept the pre-school up I'll do everything the same. 32 00:02:37,490 --> 00:02:43,190 You can reduce the clock size of the ATC here by choosing a different pre-schooler if you want. 33 00:02:43,220 --> 00:02:44,450 I'm keeping it to the default. 34 00:02:44,450 --> 00:02:46,800 I'm keeping the resolution to the default. 35 00:02:46,880 --> 00:02:52,430 The only thing I change or what is required for time a trigger is to select the extend or treat our 36 00:02:52,430 --> 00:02:58,170 source and then the type of the source so I've chosen time to trigger out event. 37 00:02:58,260 --> 00:03:03,080 Yeah cause we're using timer too in its default trigger mode right. 38 00:03:03,110 --> 00:03:03,650 Moving on. 39 00:03:04,340 --> 00:03:05,330 So yeah. 40 00:03:05,390 --> 00:03:09,610 And then finally for the ATC we have to enable the interrupt for the ADC. 41 00:03:09,620 --> 00:03:13,710 So I just come over here and take here to enable my click OK. 42 00:03:13,880 --> 00:03:16,710 Next let's go to the timer settings. 43 00:03:16,720 --> 00:03:17,800 I'll click over here. 44 00:03:17,810 --> 00:03:23,150 Time to show us we know by default our time a speed our time clock soars. 45 00:03:23,150 --> 00:03:30,500 The internal clock soars twice the time of which forty eight megahertz so to bring the unit into into 46 00:03:30,500 --> 00:03:36,320 milliseconds we have to divide it by forty eight thousand because I explained that already in the time 47 00:03:36,320 --> 00:03:44,420 of videos as we said forty eight megahertz implies forty eight million cycles per second. 48 00:03:44,420 --> 00:03:48,610 Therefore how many cycles do we need to get a millisecond. 49 00:03:48,670 --> 00:03:51,500 And that's just forty eight thousand. 50 00:03:51,500 --> 00:03:57,220 So if I put forty eight thousand here as a preschooler then my time or units becomes milliseconds. 51 00:03:57,240 --> 00:04:00,680 And over here the count period becomes this sampling period. 52 00:04:00,680 --> 00:04:02,030 Or if your ADC. 53 00:04:02,030 --> 00:04:06,670 So if you are trying to sample a particular signal you put a sampling rate here. 54 00:04:06,710 --> 00:04:13,540 So let's say we want to sample our ADC at let's say 50 milliseconds. 55 00:04:13,700 --> 00:04:19,070 So I'm just going to put 50 here and you can convert this to frequency one or about 50 milliseconds 56 00:04:19,110 --> 00:04:25,200 would give us the sampling frequency so once that is done you don't need to configure anything else. 57 00:04:25,220 --> 00:04:33,020 We just click OK then generated the code so we could bring the timer down to millisecond unit and then 58 00:04:33,020 --> 00:04:35,650 we set our sampling period. 59 00:04:35,670 --> 00:04:39,810 Now we click OK they would come to the code generation. 60 00:04:39,950 --> 00:04:49,840 Then I give my project and then ADC time trigger it is a time I trigger and then I select my two chain 61 00:04:49,840 --> 00:04:52,990 as the call you vision five click. 62 00:04:53,030 --> 00:04:56,080 By here and then it generates the code. 63 00:04:56,080 --> 00:04:59,820 Once that is done I click to open my projects like this 64 00:05:03,870 --> 00:05:06,690 then like I always do I'll just rebuild everything. 65 00:05:09,190 --> 00:05:11,380 Then I would just update my. 66 00:05:11,450 --> 00:05:17,030 Come over here click here and then take care. 67 00:05:17,660 --> 00:05:22,320 OK then ok I'll expand here and inspect my code. 68 00:05:22,410 --> 00:05:25,100 Now open may not see right. 69 00:05:25,120 --> 00:05:25,640 Moving on. 70 00:05:26,780 --> 00:05:33,170 So before we we able to get the ADC conversion when first nature started timer and the ADC. 71 00:05:33,320 --> 00:05:42,800 So I'm going to come over here and the main function I'm going to see how T I N for timer base starts. 72 00:05:42,890 --> 00:05:47,400 That's the name of the API. 73 00:05:47,460 --> 00:05:54,300 This this function takes the time a handler as its arguments and we have the time a handler defined 74 00:05:54,320 --> 00:06:02,380 up there it is h t I m too cautious time of two and which starts at a time on the stage. 75 00:06:02,390 --> 00:06:14,860 Next we have to study ADC and I can see how ADC starts and this time we want to stop the ADC would interrupt. 76 00:06:14,860 --> 00:06:19,180 Remember we take the box to allow ADC Globo interrupt. 77 00:06:19,180 --> 00:06:26,770 Therefore we have to use to start to interrupt API and I select this and then I just put the argument 78 00:06:26,770 --> 00:06:28,860 here which is the ADC handler 79 00:06:32,090 --> 00:06:33,180 like this. 80 00:06:33,350 --> 00:06:38,780 And once we have this actually we have to create a global variable like we did before to start our is 81 00:06:38,780 --> 00:06:43,390 the conversion Valley in to on this coyotes Central Valley. 82 00:06:43,640 --> 00:06:49,730 So because we are using interrupt we have to use a callback function to implement what happens when 83 00:06:49,730 --> 00:06:55,820 the interrupt Cass to find a particular callback function use with the adc can just come over here and 84 00:06:55,820 --> 00:07:03,440 then select the ADC module to see I'll just expand here and it's called Hall ADC conversion complete 85 00:07:03,770 --> 00:07:12,530 callback should be somewhere here this one here so we can read about it it says regular conversion completes 86 00:07:12,530 --> 00:07:19,250 callback in a non blocking mode pointer to ADC thus yeah blah blah blah we know this we did this with 87 00:07:19,250 --> 00:07:26,790 the the would it time a callback so we just copy this and then we redefine it without the weak key word 88 00:07:27,030 --> 00:07:35,830 I just put us here I just put it somewhere down here just keep this here and what I'm going to do is 89 00:07:35,890 --> 00:07:41,740 I'm just going to stall my ADC I'm just going to store the value of the ADC conversion in my variable 90 00:07:41,740 --> 00:07:48,660 here I'm going to see sense of I do it cause whole ADC get for you and this function takes the ADC handles 91 00:07:48,760 --> 00:07:53,940 its arguments so I just put her ADC 1 and then it's fine. 92 00:07:54,040 --> 00:07:59,770 So what's going to happen is every 50 milliseconds the funding of the ADC is screened to be collected 93 00:07:59,770 --> 00:08:06,390 and stored in the in the sense of value variable we've declared in our experiment we are using their 94 00:08:06,400 --> 00:08:07,420 potential meta. 95 00:08:07,450 --> 00:08:13,210 So this really doesn't demonstrate the the effect of what we are doing here but you can imagine you 96 00:08:13,210 --> 00:08:19,390 had a sense or like a temperature sensor or a heart rate you've designed a heart rate hardware and you 97 00:08:19,390 --> 00:08:25,600 want to acquire the heartbeat every 10 milliseconds automatically every 10 milliseconds it will sample 98 00:08:25,600 --> 00:08:32,860 it into the particular array or data structure that you've defined to store that type of data by no 99 00:08:32,860 --> 00:08:33,510 example. 100 00:08:34,360 --> 00:08:39,790 It's just going to be taken to the potential meta value and storing it in this variable here. 101 00:08:39,880 --> 00:08:45,520 So I'm going to rebuild my project and then download onto my board. 102 00:08:45,610 --> 00:08:48,930 So really this the limits of this experiment. 103 00:08:49,330 --> 00:08:55,200 So as time goes on I'll find another sensor that actually requires precise sampling rate and then we'll 104 00:08:55,210 --> 00:09:01,390 demonstrate to verify that indeed our system is something that's 50 milliseconds but this is how to 105 00:09:01,390 --> 00:09:05,460 initialize and deploy timeout triggered a DC conversion. 106 00:09:05,470 --> 00:09:11,290 If you have any questions or you need further elaboration do send me a message and I will see you in 107 00:09:11,290 --> 00:09:12,430 the next lesson.