1 00:00:00,870 --> 00:00:01,260 Hello. 2 00:00:01,290 --> 00:00:02,040 Welcome back. 3 00:00:02,040 --> 00:00:04,590 So let's implement a what you call your driver. 4 00:00:05,310 --> 00:00:09,290 So I'm gonna start with the um the directives. 5 00:00:09,570 --> 00:00:15,510 Um for those of you who don't know there is a prerequisite for this course before you take this course 6 00:00:15,510 --> 00:00:24,280 I expect you to take the um the um arm assembly program it from ground up of course and in that course 7 00:00:24,280 --> 00:00:30,750 we went through the instructions step by step the directives step by step we'll explain everything. 8 00:00:30,880 --> 00:00:31,840 So over here. 9 00:00:32,550 --> 00:00:38,470 Yeah I'm not gonna be explaining the instructions under directives much I'm just going to I'll be demonstrating 10 00:00:38,500 --> 00:00:46,350 how we use those instructions and directives to write usable um drivers for our microcontroller board. 11 00:00:46,360 --> 00:00:52,750 So for those of you who haven't taken that course I would suggest you stop this course and then give 12 00:00:52,770 --> 00:00:54,960 you the first few lessons. 13 00:00:55,420 --> 00:01:01,630 Up to the point where you um you view the lessons on directives and instructions and then you can continue 14 00:01:01,630 --> 00:01:02,090 here. 15 00:01:02,260 --> 00:01:05,110 You can send me a message I'm gonna send you a coupon for that you need. 16 00:01:05,110 --> 00:01:08,300 No you know buy it at it's expensive price. 17 00:01:09,410 --> 00:01:13,300 Um so I'm gonna start off by using the area directive 18 00:01:18,800 --> 00:01:22,960 text and this the code area is read only 19 00:01:28,390 --> 00:01:29,890 gonna align to 20 00:01:32,930 --> 00:01:34,120 it firm over here. 21 00:01:34,150 --> 00:01:38,170 This the entry and then I'm gonna export 22 00:01:41,870 --> 00:01:53,510 on it's gonna escort me like this is gonna school me and I'm gonna start off by enabling I'm gonna start 23 00:01:53,510 --> 00:02:02,000 off by branch into a subroutine to enable our GPL you call this GPL you in it and then let's implement 24 00:02:02,030 --> 00:02:07,600 GPL your niche no GPL you underscore in it. 25 00:02:07,700 --> 00:02:12,580 So we start off by enabling the clock access for Port Pete. 26 00:02:12,980 --> 00:02:19,100 If we had to write this in bare metal embedded C using CRM says R2 says control like this 27 00:02:23,000 --> 00:02:32,120 and then our C GC GPL you and then I'll use this I'll put a vertical sign for all and then I'll take 28 00:02:32,390 --> 00:02:34,120 the symbolic name we create it. 29 00:02:35,210 --> 00:02:36,100 Right. 30 00:02:36,140 --> 00:02:41,640 And this would enable clock access to port C this is a comment right in assembly. 31 00:02:41,720 --> 00:02:44,280 So this is what we're going to implement. 32 00:02:44,630 --> 00:02:52,730 So to do that we need to load the address of this GPL u r c GC GPL you I'll say load 33 00:02:55,730 --> 00:03:00,320 our 1 equals we have the address here 34 00:03:04,970 --> 00:03:14,030 and then I'm going to load take basically to use this in plain language what this is I'm gonna see take 35 00:03:14,120 --> 00:03:17,850 our issue out to take um. 36 00:03:18,410 --> 00:03:26,090 So basically this means take take the content of it. 37 00:03:26,210 --> 00:03:28,100 How do I put this in plain language. 38 00:03:32,490 --> 00:03:38,990 Take the content of what is located at at any one input into our view. 39 00:03:39,870 --> 00:03:42,860 So something is located at r 1. 40 00:03:42,880 --> 00:03:44,780 All I want is pointing to something. 41 00:03:45,840 --> 00:03:49,230 Take the content of what our one is pointing to and put into our series. 42 00:03:49,260 --> 00:03:56,170 So in effect we take the content of the current content of system control RC GC GPL you register input 43 00:03:56,190 --> 00:03:59,900 into our 0 I'm gonna perform an operation of that. 44 00:04:00,960 --> 00:04:10,690 When I say Oh Iris you are 0 and then GPL you enable. 45 00:04:11,100 --> 00:04:19,160 So so after that after this line what is in this register is gonna be put in R2. 46 00:04:19,350 --> 00:04:21,310 So we're gonna take what is an Irish U. 47 00:04:21,330 --> 00:04:24,650 And then we perform an operation would you call you f enable. 48 00:04:24,690 --> 00:04:27,010 Which is the symbolic name we created here. 49 00:04:27,050 --> 00:04:28,490 I store it back into our Sera. 50 00:04:28,500 --> 00:04:31,670 We can use to operations if we use to operations. 51 00:04:31,770 --> 00:04:32,850 It means that resort. 52 00:04:32,850 --> 00:04:37,140 This is the source number two as well as the destination. 53 00:04:37,140 --> 00:04:40,060 So we can keep it like this and it's gonna be stored in our ship. 54 00:04:40,920 --> 00:04:41,220 Right. 55 00:04:41,220 --> 00:04:42,800 Once this is that is done. 56 00:04:43,200 --> 00:04:48,900 Meaning we've modified what is an Irish you don't know we can write the new contents of Irish you at 57 00:04:48,900 --> 00:04:58,480 the location of this register in effect at the location of this um um at the location of this address. 58 00:04:58,530 --> 00:05:05,040 The reason why when I see red is that I always freeze is that we've got registers Irish who are 1 are 59 00:05:05,040 --> 00:05:07,910 two or three and business are registered to. 60 00:05:08,010 --> 00:05:12,780 But when I say this reg is that are you thinking there's any cortex is it. 61 00:05:12,920 --> 00:05:16,910 Um is it the system going through our GC register. 62 00:05:16,920 --> 00:05:21,480 Or is it the register in the register bank such as Irish you are one. 63 00:05:21,520 --> 00:05:27,110 So what I do is oh endeavor to call these addresses or although the outrageous this or refer to them 64 00:05:27,110 --> 00:05:31,510 at as this address read them register that to limit confusion. 65 00:05:31,800 --> 00:05:37,560 Anyway if you if at any given point you you have a question just send me a message. 66 00:05:37,560 --> 00:05:39,820 I don't know how this is going thus far. 67 00:05:39,840 --> 00:05:45,010 Cos I keep explaining random stuff by should you find yourself confuse the boy a little thin. 68 00:05:45,030 --> 00:05:46,280 You can send me a message. 69 00:05:47,000 --> 00:05:48,020 Um. 70 00:05:48,510 --> 00:05:48,860 Right. 71 00:05:48,900 --> 00:05:50,850 So we going to use this for instruction. 72 00:05:50,850 --> 00:05:53,510 I'm gonna say you stole the source. 73 00:05:53,540 --> 00:05:54,750 I just ask you. 74 00:05:54,750 --> 00:05:55,980 And then I have one here. 75 00:05:56,040 --> 00:05:59,610 So after this we would have executed this. 76 00:06:00,240 --> 00:06:00,700 Right. 77 00:06:02,280 --> 00:06:12,180 And we can allow some time to finish activating by using the new operation A.P. A.P. A.P. this would 78 00:06:12,180 --> 00:06:16,360 just allow some time it's like Yeah wait a bit. 79 00:06:17,860 --> 00:06:18,200 Okay. 80 00:06:18,960 --> 00:06:31,510 So now the next thing to do would be to set up a whopping to output pin a red pin red over here. 81 00:06:31,510 --> 00:06:37,880 We need to set it as output and we do that by accessing the display of direction register. 82 00:06:37,960 --> 00:06:41,150 So in C language how do you spell you f desire. 83 00:06:42,990 --> 00:06:45,790 And then I'm going to say 0 x 84 00:06:48,610 --> 00:06:50,800 0 2. 85 00:06:51,460 --> 00:06:56,460 I'm gonna do this but we've already created a symbolic name for 0 extra 2. 86 00:06:56,620 --> 00:07:05,950 I should point out 0 0 2 is the same US is the same as um is the same as this. 87 00:07:05,950 --> 00:07:07,340 Why do I say that. 88 00:07:07,390 --> 00:07:14,880 Cos if I explain this you were X 0 2 to it s binary form 0 end up with 0 b 1 2 3 4. 89 00:07:15,100 --> 00:07:17,770 And then one two one zero. 90 00:07:17,890 --> 00:07:19,130 Right. 91 00:07:19,420 --> 00:07:24,260 So this 0 this hexadecimal 0 does. 92 00:07:24,660 --> 00:07:25,520 Sorry about that. 93 00:07:25,700 --> 00:07:29,940 This hexadecimal 0 corresponds to this for binary zeros. 94 00:07:30,250 --> 00:07:35,170 This 2 in binary form will give us this uh this 2. 95 00:07:35,560 --> 00:07:37,330 Yeah. 96 00:07:37,510 --> 00:07:41,170 If we convert it to binary 4 bits binary does what we get. 97 00:07:41,200 --> 00:07:46,730 So this is the same US shift uh shift in one at position number one to number one. 98 00:07:46,750 --> 00:07:49,340 So this is bits numbers zero a bit to number one. 99 00:07:49,360 --> 00:07:54,340 So if I do this I'm saying shift 1 2 bits. 100 00:07:54,340 --> 00:08:01,930 Number 1 which is the same as having this which is the same as having this in hexadecimal code right. 101 00:08:01,930 --> 00:08:04,260 And we gave a symbolic name to this. 102 00:08:04,480 --> 00:08:09,200 This shift one at the position number 1 we call that OLED red. 103 00:08:09,970 --> 00:08:12,520 So I'm gonna copy LCD red and put it here like this. 104 00:08:14,410 --> 00:08:14,960 Um 105 00:08:17,840 --> 00:08:23,060 I'm gonna see like this I'm just gonna over come into this okay. 106 00:08:23,060 --> 00:08:28,350 Right as the course goes on I'm gonna reduce the amount of comments I use. 107 00:08:28,880 --> 00:08:32,380 Okay so this is the C language estimate and assembly. 108 00:08:32,390 --> 00:08:47,480 I'm gonna say load R 1 GPL u f D.A. R register and then load r 0 109 00:08:50,640 --> 00:08:53,750 are 1 and then I'm gonna perform all 110 00:09:02,740 --> 00:09:14,640 o r as you are sure I can use a single upper hand over here I had to bring the number sine sorry I'll 111 00:09:14,970 --> 00:09:21,130 let you read then I can write a book by using the store operating. 112 00:09:21,270 --> 00:09:27,920 Oh operator store the store instruction I should say store like this. 113 00:09:28,280 --> 00:09:28,620 Okay. 114 00:09:28,640 --> 00:09:31,250 Now we have set this as output 115 00:09:36,820 --> 00:09:38,760 I'll put more comment here. 116 00:09:38,800 --> 00:09:44,350 Set p f 1 as output. 117 00:09:44,410 --> 00:09:45,750 What we just did. 118 00:09:52,770 --> 00:09:53,730 Enable clock 119 00:09:58,250 --> 00:10:01,850 access to port F right. 120 00:10:01,910 --> 00:10:02,810 That's what we did here. 121 00:10:02,810 --> 00:10:06,020 Now we're going to 122 00:10:11,070 --> 00:10:22,980 digitally enable Pier One so to do this and see language oh would do chippy i o f d end for digital 123 00:10:22,980 --> 00:10:24,160 and they would register. 124 00:10:24,720 --> 00:10:30,810 No I'm simply going to do this early do read again I'm right and the same thing but this time to the 125 00:10:30,810 --> 00:10:32,980 digital enabled register. 126 00:10:33,210 --> 00:10:33,640 Right. 127 00:10:33,660 --> 00:10:36,000 So in assembly language how well you cried. 128 00:10:36,000 --> 00:10:41,730 Could you post a video and try to enable this in assembly language you can look about what we did over 129 00:10:41,730 --> 00:10:43,530 here and over here. 130 00:10:45,570 --> 00:10:45,960 Right. 131 00:10:46,230 --> 00:10:49,710 So once you write down we can do it together. 132 00:10:49,890 --> 00:10:50,490 I'm gonna do. 133 00:10:50,490 --> 00:10:50,880 Load 134 00:10:53,540 --> 00:11:18,270 one course GPA F D E N R and then load are sure I run and then O R Syria a lady red and then store our 135 00:11:18,380 --> 00:11:20,690 0 R1. 136 00:11:21,250 --> 00:11:28,780 Once that is done we are done with this subroutine we can return from the subroutine by using the B 137 00:11:28,840 --> 00:11:33,530 X L are like this okay. 138 00:11:34,110 --> 00:11:35,320 Right. 139 00:11:35,910 --> 00:11:37,390 So now we are done. 140 00:11:37,390 --> 00:11:40,370 Next less write a subroutine to turn on the LCD. 141 00:11:40,390 --> 00:11:43,260 I'm going to call this early on. 142 00:11:43,300 --> 00:11:58,620 Come over here and have sorry for the lady on over here and then we start off by loading the data register. 143 00:11:58,630 --> 00:12:09,640 Remember to turn it on we need to write 1 2 the P F two P F one of the data register of port F and because 144 00:12:09,640 --> 00:12:16,780 the LCD connector there when we write one that the LCD in effect will be turned on so I'm going to show 145 00:12:16,780 --> 00:12:31,210 you how to do this C language GP I o f data and then um thus we can use friendly programming again is 146 00:12:31,230 --> 00:12:35,920 simply right in additive red I think. 147 00:12:35,950 --> 00:12:36,190 Yeah. 148 00:12:37,230 --> 00:12:38,860 Okay. 149 00:12:39,370 --> 00:12:41,270 So I'm gonna do load. 150 00:12:41,270 --> 00:12:48,330 I'm going to load the address. 151 00:12:50,720 --> 00:12:52,420 I have a typo here. 152 00:12:52,420 --> 00:12:53,260 There should be d I. 153 00:12:53,320 --> 00:12:55,510 Ah okay. 154 00:12:55,900 --> 00:13:02,860 So GPL you f data from the school are 155 00:13:05,630 --> 00:13:06,150 and then 156 00:13:09,900 --> 00:13:11,890 this is going to be a simple move. 157 00:13:13,200 --> 00:13:15,520 Oh do you move into register. 158 00:13:15,530 --> 00:13:21,930 Are you do you read and then store it 159 00:13:27,730 --> 00:13:37,630 and then be X a la and then a line and then end. 160 00:13:38,530 --> 00:13:39,050 Right. 161 00:13:42,300 --> 00:13:42,660 Okay. 162 00:13:44,010 --> 00:13:44,400 Okay. 163 00:13:44,400 --> 00:13:46,350 We look good. 164 00:13:46,350 --> 00:13:50,430 So what I'm gonna do is I'm going to call this subroutine as well. 165 00:13:52,350 --> 00:13:56,420 So we start off by enabling our what she you. 166 00:13:56,430 --> 00:14:03,360 Once we've done that we're going to branch to turn on the entity and then we're going to create a loop 167 00:14:03,420 --> 00:14:08,320 by branch in by branch into the top over here. 168 00:14:08,380 --> 00:14:16,350 Be such that after we turn on the LCD and we execute this next line it's going to take us back to the 169 00:14:16,350 --> 00:14:17,070 top. 170 00:14:17,190 --> 00:14:18,020 Back to the top. 171 00:14:18,030 --> 00:14:18,750 We come back. 172 00:14:18,750 --> 00:14:20,250 We turn on the LCD. 173 00:14:20,400 --> 00:14:22,050 This is going to take us back to the top. 174 00:14:22,050 --> 00:14:24,810 In effect this is our wall one loop. 175 00:14:24,810 --> 00:14:30,120 So now let's test well we have right. 176 00:14:30,140 --> 00:14:38,290 So I'm going to set up my debugger or come to target options over here under debug dropdown still areas 177 00:14:38,320 --> 00:14:44,870 ICD I CDI click on settings and then I'm going to click reset to run. 178 00:14:44,870 --> 00:14:45,550 Okay. 179 00:14:45,570 --> 00:14:52,160 And then okay and then I'm going to click here to build up here. 180 00:14:52,400 --> 00:14:53,690 It's built successfully. 181 00:14:53,690 --> 00:14:55,590 Click here to download onto my board. 182 00:14:55,600 --> 00:15:01,060 It's downloaded and my Elegy is not on let's see 183 00:15:04,610 --> 00:15:05,840 um. 184 00:15:06,100 --> 00:15:09,880 Let's let's check our code from the top. 185 00:15:11,660 --> 00:15:18,880 Um I think the reason this the reason the LCD or Blinken is from the source that base the system control 186 00:15:18,880 --> 00:15:22,170 base address here I'm skeptical about this address. 187 00:15:22,180 --> 00:15:26,770 Let's go to the data sheet and um see um. 188 00:15:27,160 --> 00:15:28,000 Come over here. 189 00:15:28,030 --> 00:15:30,810 I'm gonna search. 190 00:15:31,810 --> 00:15:37,500 I'm gonna search system control base address and then um it's a problem here. 191 00:15:37,540 --> 00:15:39,120 You can stuff from the top. 192 00:15:39,240 --> 00:15:44,440 I simply type system control base address and then is promo here. 193 00:15:44,440 --> 00:15:52,390 Register map as the offset listed as Exodus more increment to the registers relative to the system control 194 00:15:52,390 --> 00:15:53,720 base address. 195 00:15:53,860 --> 00:15:57,070 So it says this is the base address of the system control. 196 00:15:57,100 --> 00:16:04,000 So I'm gonna use this is that I'm gonna copy this and I'm gonna search more and see what this is that 197 00:16:04,000 --> 00:16:09,830 persistent piece that tries given to system control base address over here. 198 00:16:09,840 --> 00:16:15,250 It talks about system control registered description all addresses given their relative to system control 199 00:16:15,250 --> 00:16:20,620 base address and thus the system control base address and range that's provided for legacy software 200 00:16:20,620 --> 00:16:21,160 support. 201 00:16:21,280 --> 00:16:24,990 Okay so it's the same address we saw earlier. 202 00:16:25,440 --> 00:16:26,230 Right. 203 00:16:27,030 --> 00:16:27,690 Okay. 204 00:16:27,850 --> 00:16:29,680 It's the same thing right. 205 00:16:34,220 --> 00:16:34,660 Right. 206 00:16:34,670 --> 00:16:39,410 So this indeed the system control base address I'm gonna use that. 207 00:16:39,470 --> 00:16:40,100 So yeah. 208 00:16:40,100 --> 00:16:45,680 Taking the system control base upgrades from the RCC base address won't work. 209 00:16:45,710 --> 00:16:45,960 Yeah. 210 00:16:45,970 --> 00:16:51,230 Sometimes they are such nuances and with experience you would know what to look for. 211 00:16:51,910 --> 00:16:52,880 Okay. 212 00:16:53,210 --> 00:16:54,240 So now let's try. 213 00:16:54,450 --> 00:17:01,460 Um I'm going to click here to build Click here to download onto my board and it's download it right. 214 00:17:01,490 --> 00:17:04,230 If you have any questions just let me know and I'll see you in the next lesson.