1 00:00:00,580 --> 00:00:00,950 Hello. 2 00:00:00,970 --> 00:00:01,540 Welcome back. 3 00:00:01,540 --> 00:00:10,000 In this lesson we shall see how to configure a y GPA port on the Texas Instrument team 4C 1 2 3 microcontroller 4 00:00:10,030 --> 00:00:12,630 using bare metal code. 5 00:00:12,940 --> 00:00:20,630 Come over here to create a new project new project and I'll keep it in a folder I've created quite a 6 00:00:20,650 --> 00:00:21,690 folder here. 7 00:00:28,140 --> 00:00:30,020 Create a new 4.0 Stories Project projects. 8 00:00:30,030 --> 00:00:32,430 I'll call this Kiki Io 9 00:00:38,650 --> 00:00:39,280 output 10 00:00:43,590 --> 00:00:46,110 and I'll call the project to tell you outputs as well. 11 00:00:46,110 --> 00:00:49,010 GPA or score output. 12 00:00:50,290 --> 00:00:53,730 Like this approach I'm going to select my board. 13 00:00:53,740 --> 00:00:56,250 It's the team for you. 14 00:00:56,460 --> 00:00:59,820 1 2 3 zero. 15 00:00:59,840 --> 00:01:01,460 Age 6 p.m.. 16 00:01:01,700 --> 00:01:02,350 Like this. 17 00:01:02,420 --> 00:01:05,470 And then I select this then okay. 18 00:01:05,730 --> 00:01:13,100 Then under CMC as I select call on the device I select start up and then okay over here and then I'll 19 00:01:13,100 --> 00:01:20,710 change the target to the name of my MCU team for C 1 2 3 and then over here. 20 00:01:20,710 --> 00:01:27,620 Source group Oh name it I rename it to APB for up and I'll come to target options right here. 21 00:01:27,700 --> 00:01:34,780 I'll say this to my extort which is 16 megahertz debug by here I'll select distilleries ICD I this one 22 00:01:34,780 --> 00:01:40,280 over here and then I'll click over here and I'll take this. 23 00:01:40,310 --> 00:01:48,390 Yeah reset and run and then okay and then OK then I'm going to come over here right click that new item 24 00:01:48,870 --> 00:01:55,790 and then I'll add to demand that c file name over here in the c file. 25 00:01:56,250 --> 00:01:56,970 So right. 26 00:01:57,810 --> 00:02:06,540 So over here in call you vision you can you perform so all you wish and provide just the complete solution 27 00:02:06,630 --> 00:02:13,700 apart from keeping our project well structured and given us the debugger and other things like the compiler. 28 00:02:13,860 --> 00:02:20,100 It also provides us with reference manuals and books when it comes to the books tab whichever microcontroller 29 00:02:20,130 --> 00:02:26,340 they use in call you vision provides the required reference my no audio available reference material 30 00:02:26,610 --> 00:02:33,840 for that particular hardware for instance we've got the TVC Tim 4C One two three data sheet here and 31 00:02:33,840 --> 00:02:39,840 we've got cortex and for generic User Guide this is because the Tim 4C One two three microcontroller 32 00:02:40,170 --> 00:02:47,440 is a cortex M4 and also we've got books here dealing with the compiler as well as cow empty K itself. 33 00:02:47,520 --> 00:02:48,660 So let's click here and see 34 00:02:51,990 --> 00:02:52,590 OK. 35 00:02:52,630 --> 00:02:56,250 It says Page Not Found this shouldn't be what's happening right. 36 00:02:56,290 --> 00:02:59,490 So Texas Instruments has to fix this. 37 00:03:00,340 --> 00:03:06,110 Often when you open here it takes you directly to the link of the PDA off of the data sheet. 38 00:03:06,160 --> 00:03:06,710 Right. 39 00:03:06,730 --> 00:03:11,140 Since the link is broken for this particular M.S. you would have to find it. 40 00:03:11,160 --> 00:03:16,720 So before we program the microcontroller in bare metal we first need to examine how its peripherals 41 00:03:16,720 --> 00:03:24,130 are connected and how its clock is connected to the various components as well as how the registers 42 00:03:24,160 --> 00:03:25,600 are arranged. 43 00:03:25,600 --> 00:03:30,900 So to do that we need to take a look at the data sheet so that is what a microcontroller. 44 00:03:31,060 --> 00:03:33,480 But we have the development board. 45 00:03:33,520 --> 00:03:34,300 Right. 46 00:03:34,330 --> 00:03:40,510 So the development board has the microcontroller on it and it provides us with certain eye or devices 47 00:03:40,540 --> 00:03:42,630 we can experiment with. 48 00:03:42,760 --> 00:03:47,380 We've got OLED here we've got push buttons here and we've got other things. 49 00:03:47,410 --> 00:03:53,320 So let's first take a look at the user guide for the development board so that we know which pins our 50 00:03:53,320 --> 00:03:56,330 LCD and push buttons are connected to. 51 00:03:56,330 --> 00:04:03,790 So then when we go to the data sheet and see how the GPI use connected to the CPE you we know exactly 52 00:04:03,820 --> 00:04:09,630 which PS to initialize in order to control whether LCD or push button. 53 00:04:09,700 --> 00:04:14,580 So I'm going to go to Google over here and I'll see Tim for. 54 00:04:15,190 --> 00:04:17,920 1 2 3 0 c 55 00:04:22,290 --> 00:04:26,090 launch pad and then I'll just I'll just search 56 00:04:30,910 --> 00:04:32,180 or search user guide. 57 00:04:32,190 --> 00:04:35,190 Let's see you guys should give us this. 58 00:04:35,190 --> 00:04:35,550 OK. 59 00:04:35,580 --> 00:04:42,300 So there's a link it TVC series the unforeseen launch part of evaluation kit use a guide right click 60 00:04:42,300 --> 00:04:42,870 this. 61 00:04:42,930 --> 00:04:49,770 So over here the the purpose of this course is not just to give you a cookbook approach such that when 62 00:04:49,770 --> 00:04:55,800 you're looking for this you do this and no the purpose is to make you a better embedded systems developer. 63 00:04:56,190 --> 00:05:01,430 So this assumes this assumes you know you're not familiar with the overseas series at all. 64 00:05:01,680 --> 00:05:02,910 You've just put this board. 65 00:05:03,480 --> 00:05:06,610 And how do you go about to program it. 66 00:05:06,630 --> 00:05:07,720 This is how you program it. 67 00:05:07,730 --> 00:05:11,760 First you take a look at the user guide and you take a look at a data sheet. 68 00:05:11,760 --> 00:05:15,370 Once you've done that you know exactly how to control the board. 69 00:05:15,510 --> 00:05:19,350 And you can apply this to any microcontroller regardless of the vendor. 70 00:05:19,710 --> 00:05:21,930 So that is why I'm taking this approach. 71 00:05:21,930 --> 00:05:25,750 I can write all the code and just tell you do this do that. 72 00:05:25,770 --> 00:05:32,090 So rather than telling you straightforward what needs to be done in this course I'm going to take you 73 00:05:32,090 --> 00:05:36,180 to the data sheet and you and I shall find information together. 74 00:05:36,260 --> 00:05:42,380 We would assume we just got this new microcontroller from Texas Instrument and we are embedded developers 75 00:05:42,410 --> 00:05:46,780 and we want to know how to program this type of microcontroller. 76 00:05:46,790 --> 00:05:52,700 So I'm going to be taking you through the steps that we often go through in order to figure out information 77 00:05:52,700 --> 00:05:58,530 about a new development board or a new microcontroller from a different manufacturer. 78 00:05:58,550 --> 00:05:59,130 Right. 79 00:05:59,150 --> 00:06:06,820 So let's take a look at this user guide so the user guide for our TVC launch part evaluation board. 80 00:06:06,830 --> 00:06:08,900 I'm going to scroll down here. 81 00:06:08,900 --> 00:06:11,420 Over here we have an overview of the board. 82 00:06:11,470 --> 00:06:15,780 It tells us what we've got it says we've got to use a switch over here. 83 00:06:15,780 --> 00:06:17,750 This is quite a use switch too. 84 00:06:17,760 --> 00:06:24,600 We've got one other one here and we've got we've got these bins here. 85 00:06:24,600 --> 00:06:31,160 It's allows us to add something on us booster pack perhaps want to expand this like head pays for I 86 00:06:31,160 --> 00:06:35,640 didn't more just like Bluetooth module Wi-Fi module et cetera. 87 00:06:35,970 --> 00:06:39,190 And we've got our attribute OLED over here as well. 88 00:06:39,360 --> 00:06:45,490 We've got a USB connector in this USP here is for our debugger and it provides post Well there's a post 89 00:06:45,640 --> 00:06:48,240 which this is another microcontroller. 90 00:06:48,240 --> 00:06:51,230 This one is for debugging and this the main microcontroller. 91 00:06:51,300 --> 00:06:56,670 This is where our program is stored right over here. 92 00:06:56,670 --> 00:06:59,200 It took us a bit about it. 93 00:06:59,240 --> 00:07:00,990 You can take a look at it if you prefer. 94 00:07:01,560 --> 00:07:10,140 But what we are truly interested in is the is the schematic diagram to see how the peripherals are connected 95 00:07:10,140 --> 00:07:16,500 to DMC how yeah the for those like the LCD and other things. 96 00:07:16,500 --> 00:07:16,790 OK. 97 00:07:16,800 --> 00:07:18,140 We've got this information here. 98 00:07:18,220 --> 00:07:22,080 User switches and Archie Chibi signals right. 99 00:07:22,080 --> 00:07:28,900 Actually I'm just going to copy all of this controversy to copy and I'm going to bring it over here. 100 00:07:28,920 --> 00:07:30,160 Let's see if it works. 101 00:07:30,330 --> 00:07:30,700 OK. 102 00:07:30,780 --> 00:07:31,530 Excellent. 103 00:07:32,010 --> 00:07:35,460 It's arranged properly so we're going to keep this information here 104 00:07:42,700 --> 00:07:47,930 so we know we've caught our switch one which is on the left. 105 00:07:47,980 --> 00:07:49,880 That's f for window switch to it. 106 00:07:49,900 --> 00:07:58,780 That's PFC you switch P if one has the red LCD and then the blue LCD is SPF 2 3 has the green LCD. 107 00:07:58,810 --> 00:08:00,900 OK good. 108 00:08:00,910 --> 00:08:05,060 So p f just means port F right. 109 00:08:05,090 --> 00:08:07,120 So we've seen this actually. 110 00:08:07,720 --> 00:08:15,070 We have what we need but if you have if you find a user guide and they use a guy doesn't give the table 111 00:08:15,160 --> 00:08:21,940 showing this type of information you often find this in the schematic diagram and over here when you 112 00:08:21,940 --> 00:08:24,430 check the schematic diagram you should see the LCD. 113 00:08:25,270 --> 00:08:26,320 So let's start from the top. 114 00:08:26,320 --> 00:08:27,120 So it is the maze. 115 00:08:27,160 --> 00:08:36,430 This schematic diagram of the main MCU connections and this is the MCU over here from the microcontroller 116 00:08:36,430 --> 00:08:37,070 diagram. 117 00:08:37,090 --> 00:08:40,810 We still see OLED red blue and green here. 118 00:08:41,140 --> 00:08:49,570 So when I assume over here I can see the red is connected to this one here P F one like this when I 119 00:08:49,570 --> 00:08:56,960 trace the wire I realized red SPF 1 and P.F. 2 has blue P 3 has green. 120 00:08:57,120 --> 00:09:03,850 And in fact P A 4 has used a switch one on PSU has used a switch to switch just by seeing this I know 121 00:09:04,530 --> 00:09:07,520 and I can enable it it registers appropriately. 122 00:09:07,750 --> 00:09:14,230 So now that we know where our entities are connected let's go and take a look at the data sheet of a 123 00:09:14,230 --> 00:09:21,910 war with our microcontroller I'm going to come over here and I'm going to search Tim for C 1 2 3 this 124 00:09:21,910 --> 00:09:28,270 time I'll say data sheets and the data sheet is about a chip that microcontroller chip is not about 125 00:09:28,280 --> 00:09:34,850 it TVC development board this is about just the ICI the MCU itself right. 126 00:09:34,960 --> 00:09:36,180 So I'll come over here. 127 00:09:36,190 --> 00:09:38,410 Texas Instruments has a link to it. 128 00:09:38,410 --> 00:09:41,670 I'll click this over here. 129 00:09:41,730 --> 00:09:42,320 Let's see. 130 00:09:42,330 --> 00:09:45,840 It's probably got over a thousand pages often long. 131 00:09:46,950 --> 00:09:47,310 Right. 132 00:09:47,310 --> 00:09:49,680 It's got 1400 pages. 133 00:09:49,680 --> 00:09:50,520 Don't be worried. 134 00:09:50,550 --> 00:09:52,210 You need not read all of it. 135 00:09:52,290 --> 00:09:55,900 In fact you probably use like 20 percent of it. 136 00:09:56,100 --> 00:09:59,270 Most of the time it's just a reference guide. 137 00:09:59,760 --> 00:10:01,570 So this the data sheet is called. 138 00:10:01,590 --> 00:10:06,490 It's table of contents over here and over here starts by saying OK. 139 00:10:06,840 --> 00:10:10,540 Architectural overview the MCU overview etc.. 140 00:10:10,680 --> 00:10:12,360 Let's take a look at the MCU. 141 00:10:12,410 --> 00:10:15,750 If you click this and it should have a diagram. 142 00:10:15,880 --> 00:10:16,450 OK. 143 00:10:16,460 --> 00:10:18,560 Excellent square diagram here. 144 00:10:18,570 --> 00:10:24,400 So this did that when we're interested in the first diagram we're interested in this this one this one 145 00:10:25,240 --> 00:10:28,370 tells us which bus are MCU. 146 00:10:28,570 --> 00:10:32,070 Which bus a particular pair four is connected to. 147 00:10:32,370 --> 00:10:37,720 So more than the microcontrollers use two types of buses. 148 00:10:37,750 --> 00:10:44,570 We've got the advanced pair for bus this one here known as the APB assuming a bit and we've got the 149 00:10:44,630 --> 00:10:52,460 advanced height the four months pass known as the HB de HB is extremely fast and with HB you can access 150 00:10:52,460 --> 00:10:59,630 a pair for using a single processor cycle if you want to access a pair full with the APB you may require 151 00:10:59,690 --> 00:11:06,510 at least three processor cycles in order to be able to do that so we have to find the bus our particular 152 00:11:06,580 --> 00:11:14,680 airflow is connected to so that we can enable clock access to the pair flow through the bus so over 153 00:11:14,690 --> 00:11:23,090 here let's see we've got GPA to GPA has an arrow starting from here and over here and it's got an arrow 154 00:11:23,090 --> 00:11:24,620 from here and here as well. 155 00:11:24,770 --> 00:11:34,460 So the GP is are connected both to the HB and the APB so we can control the GPA you or initialize the 156 00:11:34,460 --> 00:11:44,300 GPA you put using the HB bus for the APB bus something like the DMV the DMV also has both HP bus and 157 00:11:44,390 --> 00:11:52,020 APB bus so we can access using both HP and APB that you are is connected just to the APB. 158 00:11:52,350 --> 00:11:58,010 The general purpose time is just to the APB as well in the ATC test to the APD. 159 00:11:58,130 --> 00:11:59,350 Right. 160 00:11:59,360 --> 00:12:00,740 So that's good. 161 00:12:00,740 --> 00:12:04,330 So now we know the bus connection of our GPA. 162 00:12:04,430 --> 00:12:08,920 Let's go to their GP section and see how to configure the GP you. 163 00:12:09,410 --> 00:12:17,450 So I'm gonna scroll back to the table of contents and we're going to go to the GPO side of things which 164 00:12:17,470 --> 00:12:24,250 jump straight to the GP you side going to come back to the top and I'll come down here should be GPA 165 00:12:24,280 --> 00:12:25,700 somewhere down. 166 00:12:26,190 --> 00:12:26,950 Yeah we go. 167 00:12:26,950 --> 00:12:33,280 General Purpose input output so I click over here and this first starts by giving an overview of our 168 00:12:33,280 --> 00:12:34,280 GPO you. 169 00:12:34,360 --> 00:12:42,070 So it says the GPO module is composed of six physical GPO blocks each corresponding to an individual 170 00:12:42,160 --> 00:12:43,240 UK port. 171 00:12:43,240 --> 00:12:52,090 So we've got port a port B port sea port deportee and port f the GPO module supports up to 43 programmable 172 00:12:52,180 --> 00:12:59,960 input output pins depending on the pair for was being use and it goes on to give us the features assess 173 00:13:00,050 --> 00:13:03,500 up to 43 GPL use depending on the configuration. 174 00:13:03,500 --> 00:13:12,320 Highly flexible pin marks in many Multiplex and allows us to use US GPL or several peripheral functions. 175 00:13:12,410 --> 00:13:18,970 This means we can use the same GPL European can be used as a you at a DAC ADC etc.. 176 00:13:19,100 --> 00:13:21,730 We'll see how to do all of that and the penis. 177 00:13:21,740 --> 00:13:30,010 Also five fold tolerant and the port are named A2 G and we can access them through the APB bus. 178 00:13:30,080 --> 00:13:32,380 Yeah it's fair to mention the HB here. 179 00:13:32,460 --> 00:13:40,970 Okay it's talking about that here and over here it goes on to tell us that we can access using HB as 180 00:13:40,970 --> 00:13:42,380 well. 181 00:13:42,380 --> 00:13:42,960 Right. 182 00:13:43,010 --> 00:13:50,150 So you can spend some time to read if you're interested in it but we know that we've put a through F. 183 00:13:50,150 --> 00:13:51,470 So that's the take away from here. 184 00:13:51,470 --> 00:13:55,900 We know we've got a through F right to once that is done. 185 00:13:56,000 --> 00:14:04,280 We can go ahead to see if the data sheet tells us how to initialize the GPA to some data sheets go ahead 186 00:14:04,280 --> 00:14:09,460 to give you a step by step information on how to initialize a particular peripheral. 187 00:14:09,500 --> 00:14:12,950 So let's see if this data sheet from Texas Instrument does the same. 188 00:14:13,400 --> 00:14:13,880 OK. 189 00:14:13,880 --> 00:14:17,050 It's called initialization and configuration over here. 190 00:14:17,260 --> 00:14:22,200 And it says the GPA modules may be access to different memory pictures. 191 00:14:22,550 --> 00:14:30,220 The legacy our is the advanced peripheral bus and is backwards compatible with previous devices. 192 00:14:30,350 --> 00:14:37,880 The aperture is the advanced high performance bus and this is just like what we saw in the systems diagram 193 00:14:37,910 --> 00:14:45,290 we saw earlier we saw that the GPA you module is connected both to the AP and the HB. 194 00:14:45,290 --> 00:14:49,990 So we already know this and it's telling us how to decide which one to use here. 195 00:14:50,060 --> 00:14:53,990 It says These are pictures are mutually exclusive. 196 00:14:53,990 --> 00:15:01,980 The aperture the aperture enable for a given GPA port is controlled by the appropriate bits in GPA or 197 00:15:02,090 --> 00:15:04,710 HPC t l register. 198 00:15:04,790 --> 00:15:13,310 So if we want to enable a particular aperture whether APB or HP we would have to enable it using this 199 00:15:13,310 --> 00:15:15,770 register here which we shall take a look at. 200 00:15:16,130 --> 00:15:22,820 But by default we are connected to the APB so if we don't even access this register and we go ahead 201 00:15:23,030 --> 00:15:30,180 to enable our GPA report we will be using the APB but by default unless we want to switch to HB and 202 00:15:30,500 --> 00:15:36,920 over here it gives us steps it says to configure the GPA Europeans for a particular sport follow these 203 00:15:36,980 --> 00:15:37,700 steps. 204 00:15:37,700 --> 00:15:38,550 Right. 205 00:15:38,630 --> 00:15:45,800 First it says we need to enable clock to the port by setting the appropriate bids in the RC GC Can you 206 00:15:45,800 --> 00:15:50,030 register right to a bit of history here. 207 00:15:51,020 --> 00:16:00,260 So in recent years in recent decades I would say microcontroller design has been moving towards low 208 00:16:00,260 --> 00:16:09,230 power systems and previously systems had clog previously microcontroller had clock access to all parts 209 00:16:09,230 --> 00:16:10,730 of it or part of the peripheral. 210 00:16:10,790 --> 00:16:14,060 Regardless of whether you're using it or not. 211 00:16:14,060 --> 00:16:22,250 So this made the the system or the microcontroller consume more power then clock gate in mechanism was 212 00:16:22,250 --> 00:16:29,180 invented and what it clunky to mechanism means is you only enable clock to the part of the MCU that 213 00:16:29,180 --> 00:16:30,910 you want to use. 214 00:16:30,920 --> 00:16:38,180 So with a clock gating mechanism if I'm using just puts a I need to enable clock access just to get 215 00:16:38,240 --> 00:16:46,280 to port a if I'm using just the ADC module I need to enable clock access for just the ADC module I don't 216 00:16:46,370 --> 00:16:53,870 need to enable clock access to every module in the system to save power I just enable clock access to 217 00:16:53,870 --> 00:16:56,820 the peripheral or the module that I'm using. 218 00:16:56,960 --> 00:17:04,640 And over here we use the RC GC GPA you register to do the right thing that stands for propagate and 219 00:17:04,640 --> 00:17:08,000 control register which will see its full name later on. 220 00:17:08,000 --> 00:17:14,060 So that's the that's the reason why we first need to enable that clock by default the various modules 221 00:17:14,330 --> 00:17:17,010 and peripherals do not have clock enabled. 222 00:17:17,060 --> 00:17:18,140 We have to save power. 223 00:17:18,140 --> 00:17:23,420 We cannot be providing clock to each and every corner of the microcontroller so we first need to enable 224 00:17:23,420 --> 00:17:24,300 the clock. 225 00:17:24,320 --> 00:17:30,160 It says over here in addition we've got the SC GC GPL you and DC GC GPL you. 226 00:17:30,170 --> 00:17:34,370 And these are for sleep mode and deep sleep mode right. 227 00:17:34,640 --> 00:17:36,670 So this our first point we need to enable clock. 228 00:17:36,950 --> 00:17:43,910 And then it says set the direction of the GPL your port pin by using the QR code key I are registered. 229 00:17:43,940 --> 00:17:49,610 This is the direction register and this is the register which we use to decide whether our pin is an 230 00:17:49,610 --> 00:17:51,800 input being or an output pin. 231 00:17:52,220 --> 00:18:01,320 After that if we want to use the GPL for alternate functions such as ADC you at DAC SBI A2 C etc.. 232 00:18:01,430 --> 00:18:06,860 We've got to configure that alternate function in the GPA to F E L. 233 00:18:06,860 --> 00:18:11,070 This basically means keeping you alternate functions select. 234 00:18:11,240 --> 00:18:17,140 So we've got to configure the automate function in the automate function select register write. 235 00:18:17,210 --> 00:18:24,680 Once that is done if we wish to drive something high current we can use the GPA you drive register so 236 00:18:24,680 --> 00:18:31,070 we've got GPA you d are two are and I think this provides to merely arms or so and this for here stands 237 00:18:31,070 --> 00:18:37,220 for formulae arms and this eight year stands for each of the arms will verify this later but this register 238 00:18:37,250 --> 00:18:46,160 is used to increase the current produce at that particular GPA your PIN and also we can decide to put 239 00:18:46,160 --> 00:18:54,930 a GPA u up or pull it down by initialize and pull up resistor or put our resistor or an open drain resistor. 240 00:18:55,370 --> 00:19:00,980 We can decide to initialize a pull up resistor or pull down or open drain and we've got registers to 241 00:19:00,980 --> 00:19:06,710 allow us to make these elections so these are just optional selection is now first. 242 00:19:06,770 --> 00:19:08,230 The only thing we need to do. 243 00:19:08,230 --> 00:19:14,690 Actually the GPA or module on every microcontroller should have at least two registers the direction 244 00:19:14,690 --> 00:19:20,510 register and the data register after that every other thing is just optional. 245 00:19:20,510 --> 00:19:26,600 But now you can think of the clock gate and register as one of those three compulsory registers. 246 00:19:26,720 --> 00:19:30,000 Because we need to enable clock access to the port. 247 00:19:30,200 --> 00:19:36,310 So once you've got a clock to register and a direction register every other thing should be optional. 248 00:19:36,300 --> 00:19:40,780 Right and we've caught this this at a register. 249 00:19:41,140 --> 00:19:44,000 We leave the rest on we just use them when we required them. 250 00:19:44,710 --> 00:19:47,460 Let's see right. 251 00:19:47,480 --> 00:19:48,130 Right. 252 00:19:48,140 --> 00:19:49,080 Looks good. 253 00:19:49,430 --> 00:19:49,890 OK. 254 00:19:49,910 --> 00:19:53,490 So the table goes on to give us example over here. 255 00:19:53,660 --> 00:20:01,890 For instance if you are initializing a digital input you would want to set the alternate function so 256 00:20:01,890 --> 00:20:04,180 late for that being to zero. 257 00:20:04,290 --> 00:20:06,980 You will set the direction to zero. 258 00:20:07,040 --> 00:20:12,370 You said you already are registered to zero and you set the end to 1 D. 259 00:20:12,390 --> 00:20:14,090 And means digital enabled. 260 00:20:14,090 --> 00:20:20,540 Is that digital enable register and be you are pull up register and put on register you would have to 261 00:20:20,540 --> 00:20:22,450 decide which one you want. 262 00:20:22,520 --> 00:20:24,870 This doesn't apply since it's an input. 263 00:20:25,190 --> 00:20:26,330 So this is just an example. 264 00:20:26,360 --> 00:20:32,870 So that data sheet is a really useful tool for the embedded developer and it's very important that you 265 00:20:32,870 --> 00:20:33,770 get used to it. 266 00:20:33,770 --> 00:20:37,330 You get used to go into the details you to solve your your problems. 267 00:20:37,370 --> 00:20:42,950 It makes you a better programmer when it comes to embedded systems than just looking for you know something 268 00:20:42,950 --> 00:20:43,950 that's already cooked. 269 00:20:43,970 --> 00:20:49,100 And then you just copy and paste or import a library if you want to be good you've got to understand 270 00:20:49,100 --> 00:20:51,800 how to find your way around a data sheet. 271 00:20:52,850 --> 00:20:58,960 So now we have enough information actually to to stop writing code to blink our entity. 272 00:20:59,000 --> 00:21:03,910 So let's go and see how we make use of the information we've got it over here. 273 00:21:03,960 --> 00:21:10,770 I'm back here in Carl vision and this the main file so to include the header file of my microcontroller. 274 00:21:10,780 --> 00:21:16,520 I simply need to right click include file and then I'll select this file is included. 275 00:21:16,540 --> 00:21:26,340 Right so I'm gonna come down here into main to open the main function and open close and I'm going to 276 00:21:26,400 --> 00:21:32,060 open the infinite loop here while one open close as well. 277 00:21:32,220 --> 00:21:33,310 Right. 278 00:21:33,390 --> 00:21:36,340 So let's start by. 279 00:21:36,390 --> 00:21:39,210 So let's start by following the steps we read. 280 00:21:39,210 --> 00:21:43,170 First we need to enable clock access. 281 00:21:43,170 --> 00:21:44,940 Did I close this. 282 00:21:44,940 --> 00:21:45,570 No I didn't. 283 00:21:46,200 --> 00:21:48,030 So we need to enable clock access. 284 00:21:48,030 --> 00:21:51,930 Do not worry we wouldn't be spending so much time in the data sheet. 285 00:21:51,930 --> 00:21:55,320 Well when it's required we would have to find it in the data sheets. 286 00:21:55,320 --> 00:21:59,350 I think it's much more useful this way than me telling you what to write. 287 00:21:59,400 --> 00:22:01,680 So yeah just bear with the process. 288 00:22:01,740 --> 00:22:02,130 Right. 289 00:22:02,670 --> 00:22:05,950 So we would have to enable the clock access. 290 00:22:06,150 --> 00:22:09,550 Let's go and see the RCC register. 291 00:22:09,570 --> 00:22:09,930 Sure. 292 00:22:09,960 --> 00:22:18,670 Come over here you can press control F and search RCC GPO just like we saw in the initialization sequence. 293 00:22:19,620 --> 00:22:23,880 So when you search RCC there's a number of them. 294 00:22:24,420 --> 00:22:28,920 So over here when you actually come down this registers list over here. 295 00:22:28,920 --> 00:22:30,130 Page 18. 296 00:22:30,300 --> 00:22:37,820 And when you come here and you search our CTC your approach is known as the general purpose input outputs 297 00:22:37,830 --> 00:22:41,190 run more run mode clock gate in control. 298 00:22:41,250 --> 00:22:41,670 Right. 299 00:22:41,680 --> 00:22:48,790 And it's under system control over here system control and then there's RC RC GC. 300 00:22:48,870 --> 00:22:50,030 Right. 301 00:22:50,100 --> 00:22:52,290 So let's take a look up this register here. 302 00:22:52,480 --> 00:22:55,140 I'll click on it and I'm brought over here. 303 00:22:55,140 --> 00:23:01,920 This Register says the RC GC GPA register provides software capability to enable and disable GPA your 304 00:23:01,940 --> 00:23:10,050 modules in run mode when enabled and module is provided a clock and accesses to the module register 305 00:23:10,350 --> 00:23:17,620 allowed when disabled the clock is disabled to save power and accesses to the module registers generates 306 00:23:17,690 --> 00:23:18,820 a boss fault. 307 00:23:18,960 --> 00:23:19,350 OK. 308 00:23:19,380 --> 00:23:24,870 So basically we use this to enable clock access for GPL you ports. 309 00:23:24,900 --> 00:23:26,820 So let's take a look at what we've got here. 310 00:23:26,840 --> 00:23:28,570 It's 32 bit. 311 00:23:28,860 --> 00:23:32,100 Starting from Zero over here to 31 over here. 312 00:23:32,100 --> 00:23:34,010 Let's see what 0 is for. 313 00:23:34,020 --> 00:23:35,920 You can find that by coming over here. 314 00:23:36,060 --> 00:23:37,470 So bid 0 over here. 315 00:23:37,470 --> 00:23:42,500 It says it's zero GPA you put a run more clunky and register. 316 00:23:42,810 --> 00:23:46,270 If we set it to zero GPA you put a is disabled. 317 00:23:46,290 --> 00:23:54,850 If we set it to 1 GPA you put a enabled so enable and provide a clock to GPA you put a run mode. 318 00:23:54,900 --> 00:23:55,770 So that's what we do. 319 00:23:55,770 --> 00:24:01,390 We find it under our system control and the name of the register is RC GC GPA. 320 00:24:01,770 --> 00:24:03,270 Right. 321 00:24:03,390 --> 00:24:04,740 So we know how to look at this. 322 00:24:04,740 --> 00:24:06,950 Now let's go and write our code. 323 00:24:07,110 --> 00:24:07,580 Okay. 324 00:24:07,620 --> 00:24:11,570 We are back here in call you vision so to enable clock access. 325 00:24:11,610 --> 00:24:18,050 We simply say CIS control system control and then proceed GC GPA. 326 00:24:18,120 --> 00:24:24,150 Just like we saw in the data sheet and we realised that bit serial corresponds to put a switch to enable 327 00:24:24,150 --> 00:24:33,120 clock access for bit zero for port a we use pid 0 0 ball port f course our entity our entities are connected 328 00:24:33,120 --> 00:24:40,680 to port f let's see Port f I know you can guess where Port F is if zero S is for port eight and you 329 00:24:40,680 --> 00:24:48,360 can tell it up it's five will be four port F can you ever hear better number five is for QPR your port 330 00:24:48,420 --> 00:24:54,930 f run mode clock 18 so it's number five or by here we shall use this to enable clock access to port 331 00:24:54,990 --> 00:25:06,990 F so let's do that now come over here and then I'll do this I'll pass 0 x to zero over here and basically 332 00:25:07,740 --> 00:25:18,960 this is hexadecimal notation I can explain this to binary for you this means 0 0 1 0 and 0 0 0 0 we 333 00:25:18,960 --> 00:25:28,130 can have we can have other 0 0 0 0 0 0 0 but n is you in front of the 2 over here can be deleted cos 334 00:25:28,140 --> 00:25:34,080 he has no effect has I've deleted all of those zeros and I've left this yet but we cannot delete the 335 00:25:34,080 --> 00:25:35,970 zero after that no no. 336 00:25:36,030 --> 00:25:42,030 This affects the bits position so if we check this we know that the euro is for port a the second one 337 00:25:42,030 --> 00:25:49,050 is for Port B puts you port D This one is for Port e and this one about yes for Port f that is why it 338 00:25:49,050 --> 00:25:56,340 is set to 1 and if you compress this into hexadecimal mode it becomes your X to 0 and I'm using this 339 00:25:56,400 --> 00:26:02,820 operator here this is for friendly operation I can disable an equal sign here but when I if I put an 340 00:26:02,880 --> 00:26:09,390 equal sign here what happens is then to our GC GPA you register is going to be written with this new 341 00:26:09,390 --> 00:26:15,840 value so you can think of it this way if a different module lets say a different module using port a 342 00:26:16,200 --> 00:26:23,460 initialized less a better number two or better number three and I come in I initialize use in this statement 343 00:26:23,760 --> 00:26:30,510 I'm going to on initialize what was initialized before because I'm going to set bits number two and 344 00:26:30,510 --> 00:26:32,630 three to zero by writing this to it. 345 00:26:33,150 --> 00:26:40,470 So in order to enable just the bits that I want to be enabled I put the I this Fed school line operation 346 00:26:40,470 --> 00:26:49,560 here operator here such that just this is added just this is added to the the the initial value of the 347 00:26:49,560 --> 00:26:51,590 RC DC GPL you register. 348 00:26:51,750 --> 00:26:52,730 So by doing this. 349 00:26:52,800 --> 00:27:01,740 If the GC GPO register had a value before and it's five over here was it enabled five has just enabled 350 00:27:02,040 --> 00:27:08,310 and all add up bits aren't affected this just makes sure the bit I'm interested in which is bits 5 is 351 00:27:08,310 --> 00:27:09,530 the affected bit. 352 00:27:09,540 --> 00:27:11,670 So this is known as friendly programming. 353 00:27:11,670 --> 00:27:13,050 You put this here like this. 354 00:27:13,430 --> 00:27:16,370 So once we've done this we can set the direction register. 355 00:27:18,000 --> 00:27:23,000 So let's say we want to use the red LRT the red LCD connector to pick F1. 356 00:27:23,130 --> 00:27:31,380 So I'm going to come over here GPA you a direction register SDI R and then I'm going to set its direction 357 00:27:33,240 --> 00:27:35,770 because we want it as output. 358 00:27:36,240 --> 00:27:39,180 We have to set a direction to one if we want it as input. 359 00:27:39,210 --> 00:27:41,680 We have to keep its direction to zero. 360 00:27:41,820 --> 00:27:51,990 So P F one over here I can pass 2 x 2 0 x 02 here and this essentially means it's number one. 361 00:27:51,990 --> 00:28:01,140 I would explain this for you this is 1 2 3 4 0 and this is 0 x this is 0 0 1 0 here like this or bit 362 00:28:01,140 --> 00:28:05,540 0 bit 1 and bit 1 is for P F 1 right. 363 00:28:05,550 --> 00:28:10,020 Red LCD put a comment here 364 00:28:19,060 --> 00:28:23,180 and this one here I'll put a comment here as well for your revision 365 00:28:36,620 --> 00:28:43,800 so once we've set a direction register we have to enable it by accessing the digital enabled register. 366 00:28:43,800 --> 00:28:50,510 So I'm gonna come over here and see GPL a DC and is that digital enable register and because I want 367 00:28:50,510 --> 00:28:56,090 to enable P F one I'm going to pass your x 0 2 Yeah as well. 368 00:28:56,510 --> 00:29:06,040 So come over here use the sign equals zero x it's here to like this so once this is done we are fine 369 00:29:06,070 --> 00:29:10,020 we can write to the data register in order to turn on the LCD. 370 00:29:10,540 --> 00:29:13,750 So I'll simply come over here hand to keep the are you a. 371 00:29:14,260 --> 00:29:21,510 And then I'll access the data register by saying data and then I'll write 0 x or y here. 372 00:29:22,540 --> 00:29:25,310 It's sure to like this right. 373 00:29:25,390 --> 00:29:28,630 So now we're ready. 374 00:29:28,630 --> 00:29:31,280 We've written this. 375 00:29:31,630 --> 00:29:36,510 Basically what we've done is we've said set. 376 00:29:36,550 --> 00:29:43,150 So that's been one high because if X expand this is what you get. 377 00:29:43,150 --> 00:29:43,960 This is what you get. 378 00:29:43,990 --> 00:29:45,610 And this corresponds to being one 379 00:29:50,240 --> 00:29:51,220 that's been one 380 00:29:55,180 --> 00:29:58,160 that's been one digital like this. 381 00:29:58,480 --> 00:29:59,050 OK. 382 00:29:59,100 --> 00:30:01,170 So let's build and see how this works. 383 00:30:02,250 --> 00:30:06,780 I'll click over here to build and it's finished building successfully. 384 00:30:06,810 --> 00:30:11,750 Now we have to download onto a board that's two days see how it works. 385 00:30:12,060 --> 00:30:13,050 Oh sorry about that. 386 00:30:13,050 --> 00:30:16,220 We're working with GPO port f not port a. 387 00:30:16,230 --> 00:30:21,810 So everything here should be changed to f our LTE is connected to port F 388 00:30:25,200 --> 00:30:25,890 right. 389 00:30:25,890 --> 00:30:27,140 This is the red OLED. 390 00:30:27,180 --> 00:30:29,040 It's connected to p F1. 391 00:30:29,190 --> 00:30:32,070 So everything here should be about Port f. 392 00:30:32,370 --> 00:30:36,280 Let's build again a click over here to build show. 393 00:30:36,320 --> 00:30:42,640 I'm going to click here to download onto my board and I can see the red LDS on. 394 00:30:42,810 --> 00:30:43,380 Right. 395 00:30:43,380 --> 00:30:49,500 So let's create a pseudo delay here to help explain the LCD when we get to the time a section and we're 396 00:30:49,500 --> 00:30:51,580 going to create more accurate delays. 397 00:30:51,630 --> 00:30:57,120 But over here we're going to create a very simple delay which is actually a forced DeLay. 398 00:30:58,300 --> 00:31:04,840 Our code is delayed M.S. And this is going to accept the millisecond amount as argument. 399 00:31:05,060 --> 00:31:09,200 It's a mess and I'll come over here I use a nested loop. 400 00:31:09,210 --> 00:31:15,990 Basically this this is an empirically derived value we're going to use here and this is based on the 401 00:31:16,080 --> 00:31:19,790 16 megahertz clock frequency of our system. 402 00:31:19,800 --> 00:31:26,670 So if your system is operating at a different frequency which isn't 16 megahertz this delay won't be 403 00:31:27,300 --> 00:31:27,950 accurate. 404 00:31:27,960 --> 00:31:34,670 And also this is tied to how long it takes for our call you efficient compiler to compile our stuff. 405 00:31:34,680 --> 00:31:41,450 So this also takes into account that we usually call your vision compiler here but this a pseudo delay. 406 00:31:41,520 --> 00:31:46,770 We don't care about accuracy much delay accuracy at this point when we get to the time of section we'll 407 00:31:46,770 --> 00:31:53,220 see how to create more accurate delays but this would just help us do things like blinking LCD since 408 00:31:53,220 --> 00:31:55,050 we've not studied about timers yet 409 00:32:01,940 --> 00:32:08,150 so I say for int i equal zero ice less than the parameter passed by the user a plus plus in India I'm 410 00:32:08,150 --> 00:32:20,780 going to have an inner loop I see for j equals zero G is less than J is less than three thousand one 411 00:32:20,780 --> 00:32:22,060 hundred and eighty. 412 00:32:22,100 --> 00:32:29,420 This is an empirically derived value it's derived experimentally and I said the computation is based 413 00:32:29,420 --> 00:32:33,850 on our sixteen megahertz and the compiler that we're using. 414 00:32:33,950 --> 00:32:35,710 So we just use the value as it is. 415 00:32:35,720 --> 00:32:39,070 There is no explanation behind this value really. 416 00:32:40,010 --> 00:32:45,010 So we're just open and close on empty brackets here like this. 417 00:32:45,020 --> 00:32:45,740 So this is it. 418 00:32:45,740 --> 00:32:51,650 This is going to provide millisecond delay based on the value we pass yes if we pass 10 here we're going 419 00:32:51,650 --> 00:32:53,230 to get 10 millisecond delay. 420 00:32:53,300 --> 00:32:55,760 This is not how you should be creating or delay functions. 421 00:32:55,760 --> 00:33:02,270 I repeat when we get to that part on time as we learn how to create much more precise delays and do 422 00:33:02,270 --> 00:33:05,870 things like measure event with time it's okay. 423 00:33:06,080 --> 00:33:13,250 But for now we can use this when I copy a prototype of this function and put it over here and I'm going 424 00:33:13,250 --> 00:33:16,900 to call it a delay function before I do that I'm going to cut this year. 425 00:33:16,910 --> 00:33:21,800 This one that writes to the pin I'll cut it and bring it in the main loop and then I'm going to call 426 00:33:21,840 --> 00:33:23,010 I delay M.S. 427 00:33:26,430 --> 00:33:32,160 And then I'm going to say delay hundred m s by passing one hundred here and then once that's done I'm 428 00:33:32,160 --> 00:33:44,630 going to set this low and bring this over here and then I'm going to change this to set this below. 429 00:33:44,880 --> 00:33:47,420 I'm going to use the opposite of this. 430 00:33:47,420 --> 00:33:49,680 Operator I remember this the friendly way. 431 00:33:49,680 --> 00:33:52,170 Friendly way of setting the pin high. 432 00:33:52,200 --> 00:33:58,320 This means you set only the pin you are dealing with high without affecting the other pins in the Indy 433 00:33:58,320 --> 00:34:05,040 register to do the same for setting low to set only the pin we are interested in without affecting other 434 00:34:05,040 --> 00:34:05,850 pins. 435 00:34:05,850 --> 00:34:11,430 We put no son assigned here and then a two day like this. 436 00:34:12,000 --> 00:34:12,360 Right. 437 00:34:12,360 --> 00:34:15,160 And this will set only our pin 5 pin 1. 438 00:34:15,160 --> 00:34:18,590 This was actually our pin 1 low right. 439 00:34:18,690 --> 00:34:20,090 So this was set a pin low end. 440 00:34:20,100 --> 00:34:25,770 Once we've set that I want to delay that at 100 milliseconds or pull our delay function here. 441 00:34:26,010 --> 00:34:35,050 And once that is done or click over here to compile and click over here to download onto the board I 442 00:34:35,050 --> 00:34:39,350 can see the LCD is blinking at the hundred millisecond rate. 443 00:34:39,430 --> 00:34:44,160 So this order is for this lesson if you have any questions at all regarding annual 4 we've done. 444 00:34:44,500 --> 00:34:45,370 Just send me a message. 445 00:34:45,370 --> 00:34:49,540 You're leaving the questions area and I shall see you in the next lesson. 446 00:34:49,540 --> 00:34:50,290 Have a good day.