1 00:00:00,720 --> 00:00:01,060 Hello. 2 00:00:01,080 --> 00:00:01,680 Welcome back. 3 00:00:01,680 --> 00:00:06,210 In this lesson we're going to see how to write an ADC drive. 4 00:00:06,270 --> 00:00:13,350 We're going to see how to configure our ADC to read analog inputs so I'm going to create a new project 5 00:00:13,380 --> 00:00:19,340 by coming to buy a new car new Vision project and I'll give this a name 6 00:00:26,770 --> 00:00:33,550 a cautious ADC basic and then I'll quote a project ADC basic 7 00:00:37,010 --> 00:00:48,160 then I'll select the board team 4C 1 2 3 4 h 6 p.m. and then OK then under device l select start up 8 00:00:49,780 --> 00:00:51,260 and then on the Simpsons. 9 00:00:51,270 --> 00:00:55,560 Also the call over here. 10 00:00:55,640 --> 00:00:56,870 Okay. 11 00:00:57,020 --> 00:00:59,560 Going to rename this to the name of the board. 12 00:00:59,830 --> 00:01:01,500 Tim 4C. 13 00:01:01,760 --> 00:01:03,400 One two three. 14 00:01:03,510 --> 00:01:15,460 To expand this core this up and target options set us to 16 then debug dropdown. 15 00:01:15,470 --> 00:01:19,550 Still there is a CDI settings reset and run. 16 00:01:19,550 --> 00:01:20,060 Okay. 17 00:01:20,080 --> 00:01:20,450 And then. 18 00:01:20,450 --> 00:01:21,410 Okay. 19 00:01:21,590 --> 00:01:26,020 Going to right click over here to New item to see file. 20 00:01:26,030 --> 00:01:29,090 I call it main right. 21 00:01:30,290 --> 00:01:32,870 So our team 4C 1 2 3 2. 22 00:01:32,890 --> 00:01:41,960 I see a launch pad audit Tim 4C 1 2 3 microcontroller itself comes with 2 ADC modules each of the modules 23 00:01:42,050 --> 00:01:48,500 are twelve bit in resolution to program them then we first need to take a look at the registers we need 24 00:01:48,830 --> 00:01:56,450 in order to be able to write ADC drivers so we'll talk a bit about it registers before we start writing 25 00:01:56,450 --> 00:02:03,500 the code first and we need to do like any module we need to enable proc access to the module and the 26 00:02:03,530 --> 00:02:11,870 ADC is not different to enable clock access to the ADC module we need to access the RC GC ADC register 27 00:02:12,290 --> 00:02:21,260 and whether we want to use ADC 0 or adc 1 we've got to enable the 0 or 1 bits for the appropriate ADC 28 00:02:21,260 --> 00:02:28,280 module we want to use the sample pussy queen size a part of the ADC module and this moves the conversion 29 00:02:28,280 --> 00:02:36,860 result of the ADC to one of the ADC Firefox there are 4 sample sequences they are known as SS three 30 00:02:36,920 --> 00:02:45,380 Ss to SS 1 and SS 0 each of them is associated with a faithful defy force of different sizes so these 31 00:02:45,380 --> 00:02:52,470 sample sequences also have different sizes and sizes and sizes are equal to the defy force the associated 32 00:02:52,480 --> 00:02:53,450 two. 33 00:02:53,690 --> 00:03:00,410 I'll just come over here and put a bit of a comment over here so we've got SS 0 some pussy Kwanza and 34 00:03:00,410 --> 00:03:09,080 this one can have eight samples and then we've got SS one which can have four samples 35 00:03:12,980 --> 00:03:19,640 SS simply means sample sequencer and we've got SS to which in her four samples to because the five for 36 00:03:19,640 --> 00:03:31,860 it is associated with has a depth of four and we've got SS three which can hold just a single sample. 37 00:03:31,860 --> 00:03:38,010 So in this lesson we shall be using SS 3 because we're going to be pulling the analog signal just from 38 00:03:38,010 --> 00:03:39,230 a single channel. 39 00:03:39,240 --> 00:03:41,760 So this would suffice. 40 00:03:41,760 --> 00:03:47,910 And in order to select the sample sequence to use will be we'll have to access a register known as the 41 00:03:48,510 --> 00:03:57,270 ADC 80 SS This is known as the ADC active sample sequence I register and we're going to go to this register 42 00:03:57,600 --> 00:04:03,560 and select the sample sequencer that we want to use when our sample sequence are 3 2 1 0 0. 43 00:04:03,630 --> 00:04:10,560 So yeah don't worry we're going to write code to show all of this but by now you know how to find information 44 00:04:10,560 --> 00:04:17,370 from the data sheet as well so you can just go to the data sheet go to the part on ADC and you'll find 45 00:04:17,370 --> 00:04:23,310 everything no talking at all and in fact like we saw in the earlier sections the data sheet actually 46 00:04:23,310 --> 00:04:29,310 gives us step by step on how to configure or initialize that particular module. 47 00:04:29,310 --> 00:04:31,240 So all of this is going to be found there. 48 00:04:31,290 --> 00:04:39,180 If something is unclear you can either send me a message or improve your embedded system skills by going 49 00:04:39,180 --> 00:04:47,130 to the data sheet to check up on the ADC section so there are different ways of starting their conversion 50 00:04:47,640 --> 00:04:48,950 using the ADC. 51 00:04:49,050 --> 00:04:56,100 We have the option to start the conversion using a timer P drop M and A low comparator extend or signal 52 00:04:56,100 --> 00:05:00,690 from GPO or software trigger to study conversion. 53 00:05:00,840 --> 00:05:07,500 The selection trigger for SS 3 is done via a register known as the ADC IMU ex register. 54 00:05:07,500 --> 00:05:11,840 This is known as the ADC MOX register which will use this as well. 55 00:05:12,000 --> 00:05:18,960 And this we shall use to select whether we want a software trigger P.W. more time or trigger and trigger. 56 00:05:18,960 --> 00:05:23,550 Basically means what do you want to be the trigger for the conversion to start. 57 00:05:23,790 --> 00:05:35,640 After we we decide what trigger to use we have to access at a register known as ADC P SS I to start 58 00:05:35,670 --> 00:05:42,460 the conversion every time there is new everytime this new reading from the ADC inputs Channel 2. 59 00:05:42,480 --> 00:05:46,450 Also we have 2 ADC modules and I'll show you. 60 00:05:46,450 --> 00:05:51,530 I've got this pinata here for how they are mapped to the various pins. 61 00:05:51,540 --> 00:05:53,570 So this is our ADC here. 62 00:05:53,660 --> 00:05:57,150 We just put a comment here so these are your ADC lines. 63 00:05:57,150 --> 00:06:02,750 If you want an ADC you can access from any of these lines here right. 64 00:06:03,540 --> 00:06:07,160 But again you can find this information from the data sheet. 65 00:06:07,590 --> 00:06:09,700 So this is just yet to show you. 66 00:06:10,020 --> 00:06:11,010 Right. 67 00:06:12,090 --> 00:06:15,010 So these are the ADC lines P2P. 68 00:06:15,490 --> 00:06:26,670 P 0 through P 3 PD 1 through PD 3 PD 0 actually through PD 3 and then we've got P 5 before and then 69 00:06:26,790 --> 00:06:28,410 P before 5. 70 00:06:28,410 --> 00:06:33,150 These are our ADC lines and you can choose from any of these and when you go to the data datasheet you 71 00:06:33,150 --> 00:06:36,230 would see this there as well right. 72 00:06:36,270 --> 00:06:44,700 So we can detect the end of conversion in a bit located in the ADC raw interrupter register is known 73 00:06:44,700 --> 00:06:55,800 as the ADC r i s so we can find a particular bits in this register ADC right as to know what our conversion 74 00:06:55,800 --> 00:07:01,680 is complete or not by pulling this flag we know that the conversion is complete and we can read the 75 00:07:01,680 --> 00:07:04,550 value from the ADC sequencer. 76 00:07:04,590 --> 00:07:10,170 What are we using sequence of 3 or sequence are in a sequence that are we using when we pull a particular 77 00:07:10,170 --> 00:07:13,180 bit in this register to check whether the conversion is complete. 78 00:07:13,200 --> 00:07:15,390 Once it's complete we can read the value. 79 00:07:15,390 --> 00:07:21,690 Also we have the option to use interrupt rather than pulling and we can just set an ADC interrupts to 80 00:07:21,690 --> 00:07:27,300 inform us when the conversion is complete and when the conversion is complete the data is going to be 81 00:07:27,300 --> 00:07:29,070 read automatically. 82 00:07:29,070 --> 00:07:35,520 And after reading the data from the ADC SS faithful which is the sample sequence of faithful we must 83 00:07:35,520 --> 00:07:41,210 clear the into three flag in the ADC array as we must clear a flag here. 84 00:07:41,220 --> 00:07:48,570 After reading the data so that another conversion can be detected without clearing the flag the new 85 00:07:48,570 --> 00:07:50,650 conversion cannot be detected. 86 00:07:50,850 --> 00:07:58,440 The right interrupts flag is cleared by writing to these to a particular bits in the ADC interrupt status 87 00:07:58,440 --> 00:08:02,560 register which we shall see we are talking much let's just get straight to it. 88 00:08:02,610 --> 00:08:06,830 I'm just going to wipe all of this off like I said we can find them in the data sheet. 89 00:08:07,020 --> 00:08:10,070 And yeah if you have any questions just let me know. 90 00:08:10,300 --> 00:08:12,890 But I'm going to start with a code over here. 91 00:08:12,940 --> 00:08:18,650 I'll include a board header and I'll come over here and say it into me. 92 00:08:20,660 --> 00:08:26,380 And if you didn't understand the quick preview I gave you need not worry. 93 00:08:26,400 --> 00:08:29,110 I say type I'm going to be adding comment here. 94 00:08:29,390 --> 00:08:33,470 So we start off by enabling the clock access. 95 00:08:33,530 --> 00:08:42,440 We're going to do is in this program we're going to use ADC input channel 0 and this is connected to 96 00:08:42,530 --> 00:08:49,210 P3 and we'll be using some pull sequence at three because we need just one channel right sampler sequencer 97 00:08:49,260 --> 00:08:51,080 3s five for sizes 1. 98 00:08:51,130 --> 00:08:53,820 And since we have one channel that is sufficient. 99 00:08:54,050 --> 00:09:00,170 So we've got to enable clock access to this GPL European as well as enabling clock access to the ADC 100 00:09:00,170 --> 00:09:01,070 module. 101 00:09:01,070 --> 00:09:06,770 After that we've got to set the GPL open to alternate function and the alternate function we want is 102 00:09:06,830 --> 00:09:08,180 ADC. 103 00:09:08,250 --> 00:09:19,340 So I'm going to come over here and see a system control RC GC GPL you and I'm going to see over here. 104 00:09:19,330 --> 00:09:19,640 Sure. 105 00:09:19,700 --> 00:09:23,850 X 1 0 and this essentially says 106 00:09:27,390 --> 00:09:30,870 enable clock for Port E. 107 00:09:31,290 --> 00:09:32,650 That's what we have here. 108 00:09:32,730 --> 00:09:44,020 Once they start our say system control all CTC ADC and then I'm going to pass your X through one here 109 00:09:44,660 --> 00:09:45,470 and this is 110 00:09:52,440 --> 00:10:01,640 enabled clock for it is easier or just put ADC more jobs here. 111 00:10:01,650 --> 00:10:03,230 Here's what I you understand. 112 00:10:03,650 --> 00:10:09,480 If you are using ADC module 1 you can change this to the next bit which is built to. 113 00:10:09,500 --> 00:10:13,490 Once they stand we've got to initialize P3 for analog input 114 00:10:17,370 --> 00:10:26,870 and I'm going to start by saying general purpose input output e over here and I'm going to go to the 115 00:10:26,870 --> 00:10:31,190 alternate function selector register then I'm going to pass a tool here 116 00:10:34,030 --> 00:10:41,900 and this essentially says enable alternate function that's what we've done here. 117 00:10:42,020 --> 00:10:48,170 Once that's done we're going to disable digital functionality since we want the analog functionality 118 00:10:48,590 --> 00:10:55,170 over here so I'll see how you put E and digital enable register. 119 00:10:55,320 --> 00:10:59,030 I'm going to disable it by putting Amber sound over here. 120 00:10:59,120 --> 00:11:12,000 Understand you quote equal to to day and then just put a comment here. 121 00:11:12,440 --> 00:11:22,420 A digital function once that's done with code to enable the analog function by accessing the analog 122 00:11:22,420 --> 00:11:27,960 selector register to analog mode selector register. 123 00:11:28,020 --> 00:11:37,680 I say GPL you e over here and I'll see it m s e l This is the register and then I'll pass it over here. 124 00:11:37,870 --> 00:11:45,430 If you expand aid you realize that age corresponds to p 3 right age corresponds to be 3 125 00:11:51,620 --> 00:11:55,400 enable analog function. 126 00:11:55,400 --> 00:11:58,280 Once that's done you start off by 127 00:12:01,460 --> 00:12:05,780 would we initialize the ATC. 128 00:12:07,820 --> 00:12:13,210 So we stop by disabling the sample sequence at 3 before configuration. 129 00:12:13,220 --> 00:12:22,670 I'm gonna say ATC 0 over here and then a DC T S S this the sampler sequence I register and then I'm 130 00:12:22,670 --> 00:12:25,880 going to disable it by passing this over here. 131 00:12:28,550 --> 00:12:29,870 And this is 132 00:12:49,290 --> 00:12:49,590 right. 133 00:12:49,590 --> 00:12:51,150 That's what we have here. 134 00:12:51,150 --> 00:12:56,290 Once that is done we're going to select software trigger from the earmarks register. 135 00:12:56,300 --> 00:13:08,550 I'll say 80 C0 earmarks and I'm going to do and sign over here cause Tuesday and then I'm going to pass 136 00:13:08,550 --> 00:13:15,540 you x F and then one two three three zeros. 137 00:13:15,630 --> 00:13:21,570 And if you go to the earmarks register and you expand this you realize that we are disabling the bit 138 00:13:22,050 --> 00:13:25,170 and this keeps us the software trigger option. 139 00:13:26,980 --> 00:13:27,270 Right. 140 00:13:27,290 --> 00:13:28,850 So whatever you don't understand. 141 00:13:30,110 --> 00:13:32,990 If you don't understand why we're disabling bits. 142 00:13:32,990 --> 00:13:33,700 Number three here. 143 00:13:33,710 --> 00:13:39,700 By passing eight you can simply go to the digital enabled register and see what happens when bits. 144 00:13:39,710 --> 00:13:41,520 Number three is set to zero. 145 00:13:41,690 --> 00:13:44,950 And it applies to any register you see in this course. 146 00:13:45,080 --> 00:13:45,410 Right. 147 00:13:45,410 --> 00:13:51,650 That is why I started a course by showing you how to go to the data sheet locator register and then 148 00:13:52,130 --> 00:13:54,800 locate specific bits in the register. 149 00:13:54,800 --> 00:13:59,520 But if after all this you still have questions you can always send me a message. 150 00:13:59,560 --> 00:13:59,960 Right. 151 00:14:00,080 --> 00:14:06,420 So this over here we're seeing it. 152 00:14:06,510 --> 00:14:09,840 Say a software trigger conversion. 153 00:14:10,700 --> 00:14:14,730 Once that is done we are going to get input from the channel 0 154 00:14:17,550 --> 00:14:25,140 we're going to do 80 C0 over here and then I'm going to see SS x3. 155 00:14:25,440 --> 00:14:36,090 Then I'll pass you here. 156 00:14:36,140 --> 00:14:42,530 Once that's done we take one sample at a time and set a flag at the fair sample because we have just 157 00:14:42,530 --> 00:14:51,470 one sample to do them going to say 80 C0 and then SS control number three over here 158 00:14:54,370 --> 00:14:55,730 and I'll pass six over here 159 00:15:19,840 --> 00:15:26,500 and once that's done we enable ATC 0 plus sequence of three by coming back eighty six here over here 160 00:15:27,070 --> 00:15:33,240 and then it s.t. SS and then we pass a two over here like this 161 00:15:36,260 --> 00:15:43,080 and this keeps us enable SS 3 right. 162 00:15:43,080 --> 00:15:45,660 So this right here should enable the agency for us. 163 00:15:45,690 --> 00:15:50,540 Now we can go and start conversion and wait for conversion to complete. 164 00:15:50,610 --> 00:15:51,480 We do this in a. 165 00:15:51,840 --> 00:16:05,040 While one loop do well one over here open close and I'm going to say it is easier P SS I can then pass 166 00:16:05,100 --> 00:16:19,970 it over here and this essentially says start a conversion at SS 3. 167 00:16:20,650 --> 00:16:25,770 Once that's done we've got to wait for conversion complete and we do this by saying well 168 00:16:30,130 --> 00:16:39,300 80 you are right s and 8 Coursera 169 00:16:41,980 --> 00:16:43,490 we get stuck here we do nothing. 170 00:16:44,450 --> 00:16:47,960 So this is it full conversion complete 171 00:16:54,300 --> 00:16:58,230 and we're going to create a global variable here to hooded the resort. 172 00:16:58,270 --> 00:17:01,570 Can see end result. 173 00:17:01,660 --> 00:17:14,550 I'm going to come down here and see a resort because it is a zero SS five four three. 174 00:17:14,600 --> 00:17:17,040 That is where the resort is like this. 175 00:17:17,530 --> 00:17:24,860 And once they start started we've got to clear the completion of flag by doing an 86 year ISC equals 176 00:17:24,990 --> 00:17:25,930 eight. 177 00:17:26,000 --> 00:17:28,470 And this should cleared a completion flag for us 178 00:17:31,600 --> 00:17:32,140 right. 179 00:17:33,310 --> 00:17:38,500 So let's build and see if we have an arrow click over here. 180 00:17:38,670 --> 00:17:40,570 It's built successfully. 181 00:17:40,570 --> 00:17:42,960 Let's get it on our board and see how it works. 182 00:17:44,080 --> 00:17:46,530 So let's download onto our board. 183 00:17:46,630 --> 00:17:51,250 I've downloaded onto my board and this my set up of a potential meter here. 184 00:17:51,250 --> 00:17:53,530 It's got three legs and the middle leg. 185 00:17:53,530 --> 00:18:03,370 I'm going to connect to our P3 which is our ADC line P3 and then I'm going to connect the left leg to 186 00:18:03,370 --> 00:18:08,070 the three plus three vote and the right leg to the ground. 187 00:18:08,410 --> 00:18:15,640 So I've connected using these three wires the middle leg is connected to P3 over here and then the leftmost 188 00:18:15,640 --> 00:18:20,770 one is connected to ground and the right moves one is connected to three plus three over here. 189 00:18:20,770 --> 00:18:26,530 It's a simple potential meter and again you can replace this with any sense or at all I'm just using 190 00:18:26,740 --> 00:18:29,160 a potential meter to demonstrate this. 191 00:18:29,200 --> 00:18:34,480 So I'm just going to stick the potential meter into the bread board and once that is done I'm going 192 00:18:34,480 --> 00:18:37,990 to open our debugger click over here 193 00:18:47,660 --> 00:18:55,050 and I'm going to add our global variable to the watch window double click this right click and then 194 00:18:55,170 --> 00:18:56,430 up to watch window one 195 00:19:00,250 --> 00:19:00,890 and here it is. 196 00:19:00,890 --> 00:19:05,750 I'm going to right click this to disable hexadecimal display and I'm going to run the code by clicking 197 00:19:05,750 --> 00:19:09,140 over here and as you can see this the analog value. 198 00:19:09,140 --> 00:19:13,570 So I say move the potential meter you see the value change. 199 00:19:13,720 --> 00:19:14,440 Right. 200 00:19:14,470 --> 00:19:17,680 So I can move it to the opposite side. 201 00:19:17,680 --> 00:19:21,590 This is what I get right. 202 00:19:21,600 --> 00:19:22,260 So this is it. 203 00:19:22,260 --> 00:19:26,760 This is how to initialize the ADC on your TVC board. 204 00:19:26,850 --> 00:19:27,210 Right. 205 00:19:27,210 --> 00:19:31,260 If you have any questions at all just send me a message or leave them any questions area. 206 00:19:31,260 --> 00:19:38,510 And this the end of the lesson I shall see you later on disable the debug view by clicking over here.