1 00:00:00,680 --> 00:00:01,780 Hello, welcome back. 2 00:00:02,450 --> 00:00:09,740 And this lesson, we going to create another variation of our last project, which is our Ewart's our 3 00:00:09,920 --> 00:00:13,450 interrupt, we saw how to receive a single byte. 4 00:00:14,090 --> 00:00:18,830 What if we want to receive a packet and the package is made up of, say, 10 bytes. 5 00:00:19,340 --> 00:00:21,440 How do we construct this? 6 00:00:22,040 --> 00:00:24,800 So let's see one way that this can be achieved. 7 00:00:25,190 --> 00:00:25,600 Right. 8 00:00:25,790 --> 00:00:29,960 So I'm going to make a copy of the last project, number twenty six over here. 9 00:00:29,960 --> 00:00:31,190 I'll copy and paste this. 10 00:00:31,580 --> 00:00:33,260 I'll call this number twenty seven. 11 00:00:35,950 --> 00:00:36,520 And then. 12 00:00:38,900 --> 00:00:42,870 I simply call you are you are Torex receiving Puckett's? 13 00:01:03,080 --> 00:01:04,400 Puckett's basically. 14 00:01:05,590 --> 00:01:06,070 OK. 15 00:01:09,270 --> 00:01:17,000 I'm going to open this number 27 call over here, and this is our main NFR. 16 00:01:17,710 --> 00:01:19,750 OK, we still going to be using our interrupts. 17 00:01:19,930 --> 00:01:21,010 We wouldn't get rid of that. 18 00:01:21,630 --> 00:01:29,810 OK, so let's say this time, rather than just receive a single byte, we want to make make sure the 19 00:01:30,160 --> 00:01:35,950 bytes count is, let's say 10 before we we send it. 20 00:01:35,950 --> 00:01:40,480 And we would we are calling it Puckett's essentially OK. 21 00:01:43,200 --> 00:01:45,900 So what we're going to do is we go into. 22 00:01:46,880 --> 00:01:48,770 Update our you at. 23 00:01:50,360 --> 00:01:56,870 IREX enwrapped function, and we would need this function, take two argument, one would be a pointer 24 00:01:56,870 --> 00:02:02,370 to the Buffa to store the content and then the other argument will be the buffer length. 25 00:02:02,960 --> 00:02:07,450 But before we do that, we're going to declare a number of global static variables here. 26 00:02:08,150 --> 00:02:14,090 We're going to have one to tell us what IREX is in progress or not, what a reception is in progress. 27 00:02:14,270 --> 00:02:20,300 Another one will be to hold the are excellent the length of the pocket or the buffer if you meet and 28 00:02:20,300 --> 00:02:23,430 then a pointer to the buffer and then an iterator. 29 00:02:23,990 --> 00:02:27,540 So we're going to have these three this new three variables here. 30 00:02:28,520 --> 00:02:30,150 This one is the are excellent. 31 00:02:30,170 --> 00:02:36,020 This will be whether we want to receive five bytes, ten bytes and then a pointer to the buffer where 32 00:02:36,020 --> 00:02:42,080 we want to store the received data and then the iterator, of course, we would need to apply a loop 33 00:02:42,080 --> 00:02:42,430 here. 34 00:02:43,730 --> 00:02:54,140 OK, once we've done the we're going to update the, like I said, the T rex in its function. 35 00:02:54,800 --> 00:02:59,720 This is going to be the new IREX in its function is going to take. 36 00:03:01,470 --> 00:03:07,470 To argument this is a pointer to that buffer where we want to store what we receive and then the buffer 37 00:03:07,470 --> 00:03:13,470 land, I'm going to copy this new function prototype and bring it to the top here, because we have 38 00:03:13,470 --> 00:03:14,340 the old one here. 39 00:03:15,800 --> 00:03:17,360 Is the old one, the old one. 40 00:03:17,630 --> 00:03:18,680 OK, we cleaned it. 41 00:03:20,250 --> 00:03:22,810 In a way, I'll put this new function prototype here. 42 00:03:23,580 --> 00:03:25,050 OK, so. 43 00:03:26,460 --> 00:03:29,910 Why do we have this, OK, because it's got this sort of border. 44 00:03:31,170 --> 00:03:34,470 So when are we going to do this in this function? 45 00:03:34,470 --> 00:03:42,360 The first thing we're going to do is check if the if our buffer is valid, if the buffer is not pointing 46 00:03:42,360 --> 00:03:45,030 to another location, we've got to check if it's valid. 47 00:03:45,300 --> 00:03:48,390 And then we would initialize our global static's. 48 00:03:49,290 --> 00:03:49,590 We. 49 00:03:51,110 --> 00:03:52,010 We want to check. 50 00:03:54,320 --> 00:03:55,040 Over here. 51 00:03:56,990 --> 00:04:05,300 We want to make sure our X is not in progress, we said our X in progress because one is the flag that 52 00:04:05,300 --> 00:04:07,940 we used to indicate reception is in progress. 53 00:04:08,120 --> 00:04:09,440 So we want to see if we start. 54 00:04:11,540 --> 00:04:14,570 If our in progress is false and. 55 00:04:18,140 --> 00:04:20,960 If our progress is false and our buffa. 56 00:04:22,820 --> 00:04:24,140 We see it over here and. 57 00:04:28,230 --> 00:04:35,070 Buffer is not equal to normal, meaning the buffer is valid, if that's the case, then we want to go 58 00:04:35,070 --> 00:04:41,040 ahead and initialize our system for enwrapped. 59 00:04:42,400 --> 00:04:48,910 And then we want to return zero for success, so I say return to zero over here else. 60 00:04:50,510 --> 00:04:54,360 We could just see return one or return minus one here. 61 00:04:56,880 --> 00:05:00,440 OK, so this is. 62 00:05:05,440 --> 00:05:07,100 There's a better way of doing it. 63 00:05:07,150 --> 00:05:08,630 We come in check, OK? 64 00:05:08,830 --> 00:05:13,050 We've not started receiving yet and our buffer is not now. 65 00:05:13,300 --> 00:05:20,610 So what we want to do is set our course in progress to one and we want to set our bluebottles. 66 00:05:20,620 --> 00:05:23,610 You want to set a length that buffer and the iterator. 67 00:05:24,040 --> 00:05:28,930 So we simply set the global and this global variable here. 68 00:05:28,930 --> 00:05:33,480 We want to set it to the argument when I set the arguments past. 69 00:05:34,750 --> 00:05:40,420 So what a user passes here becomes our excellent and then the buffer points that they use apostacy, 70 00:05:40,420 --> 00:05:45,670 it becomes our IREX buffer that we define over here and the iterator is zero. 71 00:05:46,120 --> 00:05:49,210 And once we've done the OK, everything remains the same. 72 00:05:49,660 --> 00:05:55,030 We have our our enwrapped enabled, then we've given it a priority. 73 00:05:55,030 --> 00:05:56,490 And then with a neighborhood at an end. 74 00:05:56,510 --> 00:05:56,790 Vic. 75 00:05:58,490 --> 00:06:06,230 OK, so once that is done, now we go to our enwrapped service routine and see what we need to do there. 76 00:06:06,800 --> 00:06:12,590 So this is our interrupt service routine or interrupt request handler, OK. 77 00:06:15,330 --> 00:06:18,080 Over here, we don't need a queue anymore. 78 00:06:19,080 --> 00:06:27,350 What we would need, we would employ here is a SEMAFO, we need a SEMAFO that would be sent to our handler 79 00:06:27,360 --> 00:06:30,240 task to let him know that we received the entire packet. 80 00:06:31,450 --> 00:06:39,040 So our cue here, we would just remove that and we would have a SEMAFO here that would help us know 81 00:06:39,040 --> 00:06:45,760 that we've sent all the data and this will show us we've already seen how to use semaphores, which 82 00:06:45,760 --> 00:06:49,190 tasks this will show us how we can apply semaphores in interrupt. 83 00:06:49,540 --> 00:06:52,390 So we'll use the interrupt service routine. 84 00:06:53,410 --> 00:06:59,680 API for semaphores rather than our standard SEMAFO API, so to do this, I'll start off by creating 85 00:06:59,680 --> 00:07:03,120 the SEMAFO Hodler over here. 86 00:07:03,310 --> 00:07:06,580 It's global, so it's called IREX. 87 00:07:06,850 --> 00:07:08,140 That's the name of the SEMAFO. 88 00:07:08,740 --> 00:07:13,880 So we're going to come back to our enwrapped request handler over here. 89 00:07:14,410 --> 00:07:20,100 Currently, our enwrapped request handler just receives the data, installs it in temp file. 90 00:07:20,530 --> 00:07:20,990 OK. 91 00:07:21,700 --> 00:07:28,220 And over here, this is we had our excuse sent from Isar over here and we deleted it. 92 00:07:28,810 --> 00:07:34,510 So what are we going to do is whenever we receive data, we're going to take this data and store it 93 00:07:34,510 --> 00:07:35,700 in our IREX buffer. 94 00:07:36,550 --> 00:07:46,120 OK, so the data is going to be stored in the our buffer and the index will be iterated as well so that 95 00:07:46,120 --> 00:07:48,770 we can store the next piece of data in the next location. 96 00:07:49,330 --> 00:07:54,070 So then once we store the data in the aggregate buffer and we increment the index, we have to check 97 00:07:54,070 --> 00:08:01,120 whether the index is greater than or equal to the the are excellent. 98 00:08:03,070 --> 00:08:05,500 If that's the case, then we can send our SEMAFO. 99 00:08:05,710 --> 00:08:08,770 If that's the case, we can simply see if irex. 100 00:08:09,070 --> 00:08:09,700 Yes. 101 00:08:09,700 --> 00:08:14,620 If it's greater or we can see if it's equal to it's all the same. 102 00:08:15,100 --> 00:08:24,730 So if that's the case we simply said we see, OK, irex in progress, we set it to false or zero, we 103 00:08:24,730 --> 00:08:31,210 use it, we use an integer for this variable so we set it to force O0 like this. 104 00:08:31,940 --> 00:08:38,350 OK, and then we send our SEMAFO and whenever you are sending you also you still have to indicate whether 105 00:08:38,440 --> 00:08:41,740 you want a higher priority task to be woken or not. 106 00:08:42,220 --> 00:08:49,840 So over here we see X semafo give from ESR this the SEMAFO handle, and this is where we want to wake 107 00:08:49,840 --> 00:08:51,440 up a higher priority task or not. 108 00:08:51,460 --> 00:08:53,260 We said not to focus just like we did. 109 00:08:53,500 --> 00:08:56,950 And like I said, I shouldn't have any effect yet since we have a single task. 110 00:08:58,680 --> 00:09:05,740 OK, so once that is done, we come over here and then we load the the Processo, OK? 111 00:09:05,940 --> 00:09:07,920 So check this. 112 00:09:08,520 --> 00:09:09,810 We received the data. 113 00:09:09,870 --> 00:09:11,730 We keep storing it in our buffer. 114 00:09:11,730 --> 00:09:19,170 When the buffer iterator is equal to the IREX length, which is the length that we expect, then we 115 00:09:19,170 --> 00:09:24,780 set our progress to zero and then we send a SEMAFO to indicate we have the entire Puckett's. 116 00:09:25,200 --> 00:09:31,470 So then once the SEMAFO is sent, let's go to our handler task to see how this will be dealt with. 117 00:09:33,550 --> 00:09:34,510 I'll come over here. 118 00:09:34,540 --> 00:09:42,190 This is our task in the previous project, the handler task simply received the data using the key was 119 00:09:42,190 --> 00:09:43,550 simply received in the queue. 120 00:09:44,080 --> 00:09:50,460 OK, over here, what we're going to do is we're going to expect the semaphore. 121 00:09:50,500 --> 00:09:55,480 When we received a semaphore, then we would want to do something to the data. 122 00:09:55,480 --> 00:09:59,200 We want to prints the data, processing, the data or whatever we want. 123 00:10:00,640 --> 00:10:04,490 So what we're going to do is we're going to have a buffer here. 124 00:10:05,320 --> 00:10:06,880 I'm going to have to buffer here. 125 00:10:07,420 --> 00:10:14,170 And the reason the buffer will be, too, is because we wouldn't we wouldn't be using our you what? 126 00:10:14,440 --> 00:10:17,200 I'm going to use this buffer to store the IREX code. 127 00:10:17,560 --> 00:10:24,100 And what I mean by the IREX good is whether the data was received successfully or whether the data is 128 00:10:24,100 --> 00:10:25,840 corrupt or whatever time outlooked. 129 00:10:26,290 --> 00:10:31,870 We're going to store that information in this buffer and the actual data will be stored in our data 130 00:10:31,870 --> 00:10:36,070 here so we can come over here and. 131 00:10:37,190 --> 00:10:44,300 Let's see, for our example, we have we have this value, I'm going to define expected length over 132 00:10:44,300 --> 00:10:44,600 here. 133 00:10:47,850 --> 00:10:48,420 Let's see. 134 00:10:53,290 --> 00:10:56,680 Oh, defined as expected, expected. 135 00:11:00,340 --> 00:11:01,210 Peatland. 136 00:11:02,570 --> 00:11:05,510 So this is the expected length of the Puckett's. 137 00:11:07,300 --> 00:11:07,800 OK. 138 00:11:11,130 --> 00:11:14,490 So we've set us five, so the pocket length is five. 139 00:11:16,770 --> 00:11:18,140 I'm going to come over here. 140 00:11:21,160 --> 00:11:23,020 Where we sit, here we are. 141 00:11:24,950 --> 00:11:28,980 I come over here and initialize our code. 142 00:11:29,000 --> 00:11:38,690 I'm going to set the data, lente the IREX data, let's see our IREX data buffer has more capacity. 143 00:11:38,690 --> 00:11:41,050 It's got more space than our expected length. 144 00:11:41,210 --> 00:11:43,540 We just had expected lend to five. 145 00:11:43,550 --> 00:11:51,140 We can change that value, but our IREX data above has space for twenty 20 items. 146 00:11:51,140 --> 00:11:52,060 So we can leave this. 147 00:11:52,070 --> 00:11:53,180 It doesn't have to be the same. 148 00:11:53,600 --> 00:11:57,770 OK, so the first thing we do when we enter our. 149 00:11:59,770 --> 00:12:01,900 When we enter our Honda task. 150 00:12:03,200 --> 00:12:03,620 To. 151 00:12:05,050 --> 00:12:11,070 Just set everything here, we make sure we initialize it to zero, so I'm simply going to use a follow 152 00:12:11,110 --> 00:12:12,250 up to achieve that. 153 00:12:16,620 --> 00:12:22,830 So four inch equals zero eyes, less than the Buffa size, we simply set everything to zero. 154 00:12:23,400 --> 00:12:25,500 OK, so once that is done. 155 00:12:27,300 --> 00:12:36,090 We go into sets the time out because we want we said, OK, we expect the data, the entire pocket to 156 00:12:36,420 --> 00:12:43,860 OK within five thousand homes, which is essentially five seconds, we expect the entire Buffa to be 157 00:12:44,040 --> 00:12:47,550 the entire package to be received within this, OK? 158 00:12:47,970 --> 00:12:50,880 And this this is our oad start. 159 00:12:51,900 --> 00:12:58,920 IREX, this starts IREX enwrapped function, we don't need this, remember, we've changed our stats, 160 00:12:58,920 --> 00:13:00,270 IREX interrupts function. 161 00:13:00,270 --> 00:13:04,140 Now it's expects to document the buffer in the buffer length. 162 00:13:06,040 --> 00:13:13,210 So we're going to call our state our enwrapped function over here. 163 00:13:15,120 --> 00:13:15,990 We're going to see. 164 00:13:21,130 --> 00:13:22,300 Starts on school. 165 00:13:25,490 --> 00:13:28,350 On the school in Rob. 166 00:13:29,620 --> 00:13:31,870 And the first argument is the. 167 00:13:33,120 --> 00:13:36,780 Buffer, which we said when asteroids in our states are here. 168 00:13:38,560 --> 00:13:40,510 The second argument is the length. 169 00:13:43,470 --> 00:13:48,570 So the length of the buffer, we can pass 20 over. 170 00:13:49,560 --> 00:13:55,300 Actually, it would make more sense if we make the buffer size the same as the expected length. 171 00:13:55,320 --> 00:13:58,710 Now, simplify things, we would need to write less conditions. 172 00:13:59,280 --> 00:14:02,880 So I'll copy our expected picket line here. 173 00:14:02,880 --> 00:14:05,690 And that's going to be the size of our IREX data. 174 00:14:06,300 --> 00:14:07,740 So I'll push this year. 175 00:14:09,550 --> 00:14:13,880 And then our Étretat over here. 176 00:14:13,900 --> 00:14:20,750 So if you close your eyes less than expected puppetland and then over here when we come starts IREX 177 00:14:20,770 --> 00:14:22,640 interrupt, this is our IREX data. 178 00:14:22,900 --> 00:14:26,440 This is the land expected pocket size, OK. 179 00:14:28,250 --> 00:14:32,840 So this one will do, but we need to call this we need to call this repeatedly. 180 00:14:34,880 --> 00:14:44,270 You know, while one loop, so this over here, I'll cut it and put it over here right this bit, we 181 00:14:44,270 --> 00:14:45,370 do not need it anymore. 182 00:14:45,890 --> 00:14:48,740 So we said this is just the initialization. 183 00:14:48,980 --> 00:14:58,850 Then go over it in our IREX handler, we initialize our you AT4 are in it and then we initialize the 184 00:14:58,850 --> 00:15:02,240 buffer to store the received, uh, data. 185 00:15:02,450 --> 00:15:08,210 We call in this IREX data, we set everything to zero and then we defined a time out value that we want 186 00:15:08,210 --> 00:15:09,380 to give. 187 00:15:09,720 --> 00:15:17,000 OK, and then when we came over here in our one loop we see stats Ulriksen robt, we passed our buffer 188 00:15:17,000 --> 00:15:18,130 and then the length. 189 00:15:19,040 --> 00:15:28,010 Now we're going to take the SEMAFO that was sent or the SEMAFO that will be set will be sent from the 190 00:15:28,010 --> 00:15:29,450 interrupt request handler. 191 00:15:29,750 --> 00:15:32,800 We're going to check if the SEMAFO can be taken. 192 00:15:33,410 --> 00:15:39,950 So we see ximo photic are done the name of the SEMAFO and then the timeout which is this time of value. 193 00:15:40,190 --> 00:15:45,530 We say if this is pass, meaning if we are able to take it then. 194 00:15:47,430 --> 00:15:50,450 We can print received or something. 195 00:15:52,350 --> 00:15:57,040 We can if this is passed, then we can print a particular code. 196 00:15:57,120 --> 00:16:01,730 OK, so over here we can check what other data lenders are expected. 197 00:16:02,070 --> 00:16:03,150 So we'll see if. 198 00:16:04,460 --> 00:16:06,260 Expected PKC lenth. 199 00:16:10,660 --> 00:16:18,700 Is equal to our IREX index, remember, we have this other global variable called index, the Iterator, 200 00:16:18,700 --> 00:16:27,220 which moves through the Buffa indices, OK, it's expected LENTE is equal to the current are iterator. 201 00:16:27,550 --> 00:16:29,500 Then we know we've received all the data. 202 00:16:31,430 --> 00:16:39,710 We can see Sprint and Sprint here, this used to take a string and place it in a buffer for us. 203 00:16:42,060 --> 00:16:49,720 So go clean, see sprint over here and what we want to do is this is our buffer. 204 00:16:51,720 --> 00:16:58,500 The reason I'm using sprint efforts, we're going to be using our Ewart's in IREX mode, so we cannot 205 00:16:58,500 --> 00:16:59,310 print that. 206 00:17:00,000 --> 00:17:05,760 So we're going to take our code, the code here, because it could be a word as simple as received. 207 00:17:12,310 --> 00:17:14,830 OK, so we're going to take this story to you. 208 00:17:14,860 --> 00:17:16,900 That's what this means, Sprint F means. 209 00:17:18,580 --> 00:17:20,510 Take this and put it in this buffer. 210 00:17:21,030 --> 00:17:29,350 Okay, so if the expected length is equal to the other idea we want to store this year when a prince 211 00:17:29,350 --> 00:17:29,890 received. 212 00:17:32,210 --> 00:17:34,220 What if it's not El's? 213 00:17:45,060 --> 00:17:50,610 We want to print let's data so we can see. 214 00:17:55,360 --> 00:17:57,040 As princess over here. 215 00:17:58,530 --> 00:18:00,890 And then we still want to store here. 216 00:18:02,070 --> 00:18:05,310 You know, our xcode by far and over here we can see. 217 00:18:08,670 --> 00:18:14,280 Data are for error and we could see. 218 00:18:15,850 --> 00:18:17,170 Maybe we expected. 219 00:18:19,440 --> 00:18:24,300 A particular number, and then we've got a particular number we can see expected. 220 00:18:28,540 --> 00:18:30,460 The percentage I bite's. 221 00:18:41,350 --> 00:18:41,980 Actually. 222 00:18:45,440 --> 00:18:52,640 I simply say lenth miss much, let's not complicate complicated things decided on the right phrase to 223 00:18:52,640 --> 00:18:53,230 type here. 224 00:18:53,480 --> 00:18:56,640 OK, length mismatch. 225 00:18:56,690 --> 00:18:57,080 OK. 226 00:18:59,420 --> 00:19:00,240 And over here. 227 00:19:00,290 --> 00:19:01,620 So this is what happens. 228 00:19:01,910 --> 00:19:08,000 So meaning if we are able to receive the data within this time out, we check whether the length is 229 00:19:08,000 --> 00:19:16,070 the same, because the IREX iterator would be the number of the last data item we check. 230 00:19:16,070 --> 00:19:18,790 If that's it, we say, OK, our xcode received. 231 00:19:19,130 --> 00:19:21,170 If it's not the same, we see a length mismatch. 232 00:19:21,710 --> 00:19:24,230 What if we are not able to received within? 233 00:19:24,470 --> 00:19:29,210 We're not able to receive within the the declared time out value. 234 00:19:29,690 --> 00:19:35,470 OK, so we're going to write on this condition here to deal with a C else. 235 00:19:36,320 --> 00:19:42,700 We want to see Asprin F and over here we can see printed time out. 236 00:19:43,190 --> 00:19:45,410 You can see our xcode. 237 00:19:48,210 --> 00:19:50,190 Time out over here like this. 238 00:19:51,930 --> 00:19:53,610 OK, so we're looking good. 239 00:19:53,720 --> 00:19:55,860 Looks long, but we're looking good. 240 00:19:58,310 --> 00:19:58,730 OK. 241 00:20:00,320 --> 00:20:05,750 OK, so let's build and see what we have a click here to build. 242 00:20:07,220 --> 00:20:08,810 We have to anomaly's. 243 00:20:10,060 --> 00:20:18,670 OK, we've now included semaphores in this project, so we would come over here to our systems as well 244 00:20:18,670 --> 00:20:19,990 as the fall right. 245 00:20:19,990 --> 00:20:30,910 Click open declaration and scroll down here and I'm going to include some of the rage we spelled s m, 246 00:20:30,910 --> 00:20:35,380 p, h, r and R, OK, s. 247 00:20:37,140 --> 00:20:38,010 The schoolbook. 248 00:20:39,040 --> 00:20:41,160 Quick to run, quick to build first. 249 00:20:42,040 --> 00:20:43,490 It's built successfully. 250 00:20:45,310 --> 00:20:47,290 I'm going to right click this. 251 00:20:49,180 --> 00:20:55,150 Debuggers estimated to double click this to happen, I say, OK. 252 00:21:00,200 --> 00:21:00,960 Click the switch. 253 00:21:02,390 --> 00:21:10,340 OK, so I'm going to remove this, receive Buffa, remove all and what I'm going to do is. 254 00:21:12,130 --> 00:21:17,500 I'm going to add our data and our expert exposure, since we know we are starting to receive data in 255 00:21:17,500 --> 00:21:20,000 our school, our our data and our exposure. 256 00:21:20,020 --> 00:21:22,490 That is where they received stuff will be kept. 257 00:21:22,990 --> 00:21:24,040 So I copied this. 258 00:21:25,300 --> 00:21:26,230 Our xcode. 259 00:21:29,590 --> 00:21:33,170 And then IREX data, if we want to check the data itself. 260 00:21:34,640 --> 00:21:40,920 OK, and I'm going to open real time, real time is already here. 261 00:21:41,890 --> 00:21:43,700 I'm going to expand our Xcode. 262 00:21:43,750 --> 00:21:45,370 We gave it a length of 50. 263 00:21:46,150 --> 00:21:48,340 OK, we may need to shorten this. 264 00:21:48,670 --> 00:21:56,320 So I click play here and then I'm going to press a number of letters on my keyboard. 265 00:21:56,830 --> 00:22:00,270 I've selected this type in area of real time. 266 00:22:00,280 --> 00:22:04,990 The reason we don't see what we write is because we've no, we're not echoing what we typing. 267 00:22:05,240 --> 00:22:07,870 OK, so I'll press a number of keys. 268 00:22:10,280 --> 00:22:13,370 Let me see what I need to first open the port. 269 00:22:17,570 --> 00:22:20,120 OK, nothing is happening, I've pressed. 270 00:22:22,380 --> 00:22:29,340 You see, when I press a key, we see here, you see you see the lights here showing that I'm trying 271 00:22:29,340 --> 00:22:33,690 to transmit from here, OK, but there is nothing in our IREX. 272 00:22:35,640 --> 00:22:37,620 Could the ACARS data? 273 00:22:38,960 --> 00:22:43,220 Our data has nothing as well, so I'm going to press you stop here. 274 00:22:43,240 --> 00:22:46,030 Let's see where that's our program and. 275 00:22:47,770 --> 00:22:56,320 Config assets, PKU, hahaha, I've seen this error before, it could be that we didn't create we have 276 00:22:56,320 --> 00:22:59,330 a queue somewhere or we have a SEMAFO that we didn't create. 277 00:22:59,950 --> 00:23:06,230 Yes, whenever you don't create a feature and you try to use it, you end up at a part of the code. 278 00:23:06,880 --> 00:23:10,480 Indeed the SEMAFO wasn't created and just bear with me. 279 00:23:10,750 --> 00:23:12,550 I've made this error before. 280 00:23:13,180 --> 00:23:16,900 We just, we just declare the handle of the semaphore without creating it. 281 00:23:18,230 --> 00:23:19,750 So let's create the SEMAFO. 282 00:23:21,010 --> 00:23:28,690 So when we come over here, we create the SEMAFO by saying XML for creates binary and we store the handle 283 00:23:28,690 --> 00:23:29,330 in the handle. 284 00:23:29,380 --> 00:23:30,520 We declared over here. 285 00:23:31,210 --> 00:23:32,800 OK, let's stop this. 286 00:23:34,640 --> 00:23:38,200 OK, so click over here to build again. 287 00:23:44,100 --> 00:23:45,330 It's built successfully. 288 00:23:45,930 --> 00:23:47,460 Click here to go to Debugger. 289 00:23:53,040 --> 00:23:54,030 Click here to switch. 290 00:23:58,330 --> 00:24:01,510 OK, here we go, I'm going to expand this hour Xcode. 291 00:24:03,320 --> 00:24:05,420 And I'm going to open this. 292 00:24:05,720 --> 00:24:12,260 This is real time is still the going to click to run and then I'm going to press a number of keys on 293 00:24:12,260 --> 00:24:12,890 the keyboard. 294 00:24:14,690 --> 00:24:16,640 OK, we're still transmitting yet. 295 00:24:16,640 --> 00:24:17,450 Nothing to see. 296 00:24:18,260 --> 00:24:23,850 OK, we're going to come over here, but they're going to come over here. 297 00:24:24,830 --> 00:24:27,530 Oh, here is a it took a while timeout. 298 00:24:27,680 --> 00:24:31,210 OK, so at least something is working. 299 00:24:31,400 --> 00:24:33,860 We didn't receive the data, but we did receive a timeout. 300 00:24:34,970 --> 00:24:40,340 This is timeout t i m e o u t o uti. 301 00:24:40,340 --> 00:24:41,240 OK, timeout. 302 00:24:41,780 --> 00:24:43,780 Let's see our data buffer. 303 00:24:45,290 --> 00:24:45,740 OK. 304 00:24:46,750 --> 00:24:47,980 We received the data. 305 00:24:49,320 --> 00:24:50,700 We did receive the data. 306 00:24:51,540 --> 00:24:54,780 OK, I know what is happening here. 307 00:24:55,200 --> 00:24:55,800 Let's. 308 00:24:59,340 --> 00:25:08,600 Less comment out our spring time out, so we said if we don't receive within the timeout print, time 309 00:25:08,610 --> 00:25:08,870 out. 310 00:25:09,330 --> 00:25:11,190 I'm going to comment this out first. 311 00:25:13,870 --> 00:25:14,740 It could be that. 312 00:25:16,270 --> 00:25:23,590 We received the data and the integrity is good, but it's just a bit late, so we don't get to see, 313 00:25:24,400 --> 00:25:29,380 you know, we don't we end up seeing time out as the code in a way. 314 00:25:29,410 --> 00:25:36,610 Let's comment this out and see if we can receive the data with this call received or lenth mismatch 315 00:25:36,880 --> 00:25:40,270 before we come in and able this a click here to view it. 316 00:25:44,040 --> 00:25:46,770 It's viewed successfully or click here to go to the debugger. 317 00:25:57,780 --> 00:25:58,290 OK. 318 00:26:08,220 --> 00:26:14,640 So I'm going to click to run and then I'm going to type number of keys, OK, received. 319 00:26:16,300 --> 00:26:16,750 Right. 320 00:26:16,870 --> 00:26:22,720 So we've been able to receive I just typed what you would call gibberish, so let's see that. 321 00:26:23,350 --> 00:26:27,070 Yes, you can see USFS, OK? 322 00:26:29,410 --> 00:26:33,730 So the idea is I have to type fast enough, otherwise there'll be a time out. 323 00:26:36,140 --> 00:26:36,590 OK. 324 00:26:39,360 --> 00:26:45,630 So now let's go back, let's increase the timeout amount. 325 00:26:45,660 --> 00:26:47,430 I'm going to increase the timeout from. 326 00:26:48,920 --> 00:26:50,450 Let's say five seconds. 327 00:26:52,680 --> 00:26:55,290 To eight seconds, OK? 328 00:26:55,560 --> 00:26:56,490 Quick Hits Bude. 329 00:27:09,340 --> 00:27:11,590 And then we get to go to the debugger. 330 00:27:23,830 --> 00:27:28,510 And I'm going to type one, two, three, four, five, just so you know. 331 00:27:30,430 --> 00:27:33,400 I'm going to come over here, expand the code. 332 00:27:36,350 --> 00:27:43,080 Well, let's see, we did in a neighborhood, a time out asprin, if sorry, but let's go back and enable 333 00:27:43,440 --> 00:27:46,500 the experience of full time art is still committed. 334 00:27:46,530 --> 00:27:50,190 Art s click here to build. 335 00:27:54,320 --> 00:27:56,870 Let's build successfully go to debugger. 336 00:28:03,250 --> 00:28:03,850 Switch. 337 00:28:11,010 --> 00:28:12,420 OK, explain this. 338 00:28:15,100 --> 00:28:20,980 And we can increase the buffer here, since the code doesn't require 50 bytes so we can increase the 339 00:28:22,210 --> 00:28:22,710 OK. 340 00:28:26,010 --> 00:28:29,580 And I'm going to come over here, press this and then quickly. 341 00:28:32,710 --> 00:28:33,700 OK, received. 342 00:28:34,840 --> 00:28:36,730 So I was able to type fast enough. 343 00:28:38,800 --> 00:28:40,720 And you can see one, two, three, four, five. 344 00:28:40,930 --> 00:28:43,410 OK, so this is it over here. 345 00:28:43,630 --> 00:28:49,270 The the lesson or the take away here is we use in the semaphores to do this for us. 346 00:28:49,780 --> 00:28:54,160 The SEMAFO we are using has to be give from ESR. 347 00:28:54,610 --> 00:28:56,590 It's not just our standard SEMAFO gif. 348 00:28:56,950 --> 00:29:01,450 So we've seen how to use Qs in uninterest service routine, how to use semaphores. 349 00:29:01,660 --> 00:29:04,240 That's all there is for this lesson and I'll see you in the next lesson. 350 00:29:04,480 --> 00:29:05,260 Have a nice day.