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All right.

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Welcome back.

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So we're going to try this next example.

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We are going to create our own program to count deep carers of an event using timers.

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And as we said we are going to detect the rise and edge off of a switch in order to count the occurrence

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of this event.

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So like always you create a new folder and you create a project inside that photo that I have done that

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already I've created a new folder called event counter a new project called event contact inside a project

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and I've done all the initialization that we do.

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So I'll wait for you for a minute or so and then you catch up

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go to the target's options and do this set up here as well.

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I've done all of that so I'll dive in straight.

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We stopped by for you to know I mean the CFO right click here.

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An odd new item to group and its main see and we have the here and we are at the head of file for all

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microcontroller.

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Right here we go and we add one main function

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right.

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We are set a kid a skeleton is ready.

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Now let's add the flesh if you may.

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So let's start with it time initialization will create a new function and then we'll call this new function

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time of three a rise an edge event in it this is going to be a function that initialize as the time

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off for detecting rides and ages.

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This war is going to look like and would stop by and enabling the time we use in time at three for this

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example cause we are going to use P B2 and P B2 is connected to the general purpose time of three.

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So we stopped by by activating the clock gate and register for time three and we can just use the hexadecimal

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0 0 8.

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As you know as your ex your age is 0 0 1 meaning beyond the bit number 3 when you count from zero bits.

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Number three is time of three hence your extra eight thought out expand the air for you for the last

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time.

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Right.

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The binary code here and there's going to be one two three four.

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It's going to be one two three.

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So this is it.

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So this is it's zero for a time a zero.

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It's wonderful time a one two four time two but three four times three.

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When we convert this to hexadecimal code we get 0 x 0 8.

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Excellent.

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So the next thing we do is to activate the clock gate and register because GPI you'll be going to use

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P B2 as the input pin that we read down that event from.

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So we have to activate port B as well to would do that and then we set GPI or b been to set the pin

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to an input pin and then we digitally enable it digitally enable it.

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Then we would have to you have to configure the alternate to function automate select register as well.

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For this example.

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And thus the upscale and we would enable the alternate function register.

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And then we have to set the p control register with its specified code.

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We spoke about this in the very last lesson we just did to configure P B to us at times three C C piece

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your pain.

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We saw the table there we we saw the table with all of them listed and wall code should be useful.

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What particular peanut port.

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And this the code that corresponds to Peavey too.

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And then we continue with the configuration of the piece to this last one.

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And why is the GPL configuration as complete.

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We continue with the the time configuration and we start by disabling the time off before we stop making

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any changes to it.

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So we start by access in the time of 3 control register and we set it to series you would disable it.

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And after that we go to the time a 3 configuration register and we select periodic code mode.

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We select 16 bits mode sorry 0 0 4 corresponds to enabling 16 bits mode in D C G register you can verify

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from the data sheet.

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After that we go to the timer a mode register with this register.

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We decide whether we want a periodic mode one time one shot mode file capture mode or a trigger mode

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so we select.

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We use this particular hexadecimal code and this code set the timer a more courageous start to an app

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counter timer an edge college course we're going to call the rise and edge and set it in cup mode.

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If you take a look in the data sheet you realize that when you when you activate these particular bits

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these are the parameters you set for what it timer a mode register.

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The next thing will be to configure the timer a much register and timer much register.

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This this register sets the current limit compared to t r to determine whether much defense hustle kid

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the T will be the last register we configure.

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But this register in effect tells us how large we can count how many times can we count before.

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The limit is four right.

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Meaning you cannot count a billion times this register that much register creates down limits and currently

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is just it's just sixteen bits in size to expand to the size of how much or how many cards we can make.

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We can optically time a priest Kayla register.

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We can set up priest Kayla and this priest Kayla offices additional aid.

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So the 8 bit with this sixteen bits keeps us 24 bits so we can count up to 24 bit size so us hand the

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comment.

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This particular register issues with a time on much registered to expand it to a twenty four bit as

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the priest Kayla.

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So I hope you understand again if there is something you do not understand please leave it in the comments

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section.

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Finally we we enable the day time after we've done all the changes.

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We do this by access and the time of going to register and setting it one very straightforward.

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Once this is done this creates another function for collecting the event.

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We're going to call this function time of 3 a rise in each event to capture.

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We're going to use this function to capture the event so it's just as simple as this.

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This function is simply going to return what is in the TB register.

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Remember we said that T.

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Register is compared with a much register too determined to determine an event.

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Right.

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And as we wrote for the March register is usability compared to the TR to determine what only fantastic

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cat.

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So this is it.

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This is what it looks like.

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All the functions look like.

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So what we have to do now is come over here.

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We just place a prototype of this function up here and then place a prototype of the other function

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up there as well.

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The next thing will be to create a variable to store the counter so that we can fill in the debugger

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and see the changes that occur.

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What I'm gonna do is I'm going to create a variable called number of events going to make it global.

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I'll keep it here and what I'm going to do finally is to store the return value of all of the time up

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of the time through right rising edge events capture function in this variable.

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This function returns to the number of events that are captured in fact since we've written this year

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compared with TIME I'M MUCH TO DETERMINE much events.

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And we have compared to t R2 too much events.

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I'm just gonna clear this.

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This comment is a bit confusing.

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Oh it's a bit redundant.

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So finally before we test out the code.

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Yeah let's put in the wild as you can see it's not in the wild it's just in the main show we just opened

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our wild one which is open a while loop open and then close.

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So after we farm after we've written our while loop while one loop.

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Yes.

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Let's not forget to initialize the timer just copy and paste to her this visualization and say it like

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this.

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So we going to test this using the debug view.

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We're going to do as we enter the debug view and observe the changes that occur with the number of event

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as we press that push button.

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So you click here to go to the debug few.

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So I have a little setup here.

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I have a push button.

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It's got two legs of connected one day two to three point three forward to pin and the other leg to

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B to what's going to happen is when I press that push button the rising edge should be detected by PBT

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that the above fuse a very important part of the to chant.

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If in a very conversant with the both of you please take a look at my other calls the cortex and bare

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metal and better to see programming course with this course you learn the full range of uses of the

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debug view.

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You'll learn how to read what's going on in the memory in the registers.

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You also learn how to read the machine language as well as the disassembly code.

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So that being said for this very example we just need to observe what happens to the global variable

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we've set.

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And it is this global variable which we have named a number of events to do this.

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You just highlighted by double click on it right click and then go to a number of events to watch window

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1.

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If you add it it would appear here in watch when the one and you run your core why you want to do is

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come over here and click on to run.

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But if I click yes you can see this but is increasing because this switch that push button has been

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turned on.

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Okay now turn it off and it stopped.

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So its content five hundred and twenty one rise and just so far.

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Remember the rising edge case course the young.

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The switch was stand to click again and there and you can see it's continuing its current in the rise

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in each course there is context.

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Turn it off.

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And so this is how you are.

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You can't do your parents off on you fences and timers.

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One way of doing this.

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You can't use this to detect single presses as well rather than you know letting the columns humorously.

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You can write various algorithms or very simple coding fat to detect that it's been pressed once or

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not this is often known as the deep bounds and you can write very simple code for that in a way the

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switch is not the perfect example for the application of event counting.

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I'm using time as the best way to do this which would have been to get a signal generator and then we

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generated the signal and plug the signal to two p B2 and then we would upset a number of fries and they

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just die has been generated by the signal and compare the number of ways and ages we see to the number

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that is detected over here but because not everyone has a signal generator.

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We are using this switch to demonstrate this.

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And if you do not understand please leave your comments or your questions below.

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So to then see you in the next lesson.