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SD CARD using SPI in STM32 || Cube-IDE || File handling || uart
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Jun 26, 2019
Watch Updated Video ::: https://youtu.be/RgQt4quLh4Q
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0:04
hello everybody welcome to controllers
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Tech after receiving a lot of requests
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on the topic today I have decided to
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make a video about interfacing SD card
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with stm32 using spi mode in this video
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we will do some basic file handling this
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includes creating opening read write
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update and deleting the files other
0:32
complex functions such as directory
0:35
related and file system related
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functions will be covered in the
0:39
upcoming videos I am using stm32 f103
0:44
controller and stm32 cube ide so let's
0:49
start by creating the project in cube MX
0:57
[Music]
1:20
[Music]
1:36
select the fat F's filesystem and pay
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attention to the settings here
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[Music]
2:09
I will be using SPI one in full-duplex
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master mode also I will use you up to
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transmit data and rest is the usual
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settings
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[Music]
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[Music]
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[Music]
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[Music]
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so the project is created I will just
3:48
quickly build it once so the errors can
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be avoided
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[Music]
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[Music]
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copy the library files that we are going
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to need to the respective folders
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[Music]
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we need to include this file that we
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just copied also to use some string
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functions
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[Music]
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next open fad FSS d dot H file and use a
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disk IO H file
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here we need to link the file system to
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our driver just follow me
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[Music]
6:00
note that the arguments here should be
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same as they are in the function to
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which this is a part of
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let's build it again to check for errors
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and yes we do have some errors but don't
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worry we will get rid of them in our
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next step in the fat FSST dot C file
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make sure you define the CS port and CS
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pin that you are using also the SPI
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handler the default here is to be one
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let's close these as they are done and
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open the interrupt handler here we need
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to define our time of functions
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these timers should run independently
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and that's why it's best if we define
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them in the systick handler
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note here all letters are gone also this
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is it for the configuration let's move
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to our main function now I am creating
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some variables that I am going to use
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these include FS for file system fill
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for the file f result for storing the
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result of each operation and buffer to
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store the data which we can read or
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write
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you
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be R and B W stores the counter to the
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read and write in the file and at last
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some variables to check the capacity of
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the card
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I am writing this function send UART to
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make it easy to write the data to the
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UART
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[Music]
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[Music]
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[Music]
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buf size is used to determine the size
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of the buffer up to which it is filled
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and at last a function to clear the
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buffer
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okay let's start our main program by
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mounting the SD card first and we are
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going to use F mount function to do so
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there is some verbose in case of a
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failure next we are going to check the
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capacity of the card we are going to use
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F get free function to do so the total
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size and the free space will be sent via
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the UART
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now it's time to create our first file F
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open function is used to open a file and
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if the file does not exists it will
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create it and the no puns it here F open
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always does that job of creating file
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also ever read and F awright are the
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access given to the file next we are
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going to write some string to the file
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using F port s function and then close
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the file now in order to read it we need
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to open it with read access and then
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copy the string from the file to the
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buffer using F get s function here fill
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dot F size is the size of the data in
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the file now we need to close the file
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let's build our code and test it
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[Music]
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take a look at the output of the UART it
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shows us the total size and the free
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space in the card it also shows that the
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file was created and the string that was
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written the file this function used F
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get s and F port s to read and write
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string
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[Music]
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next we are going to take a look at the
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F right and F read functions which do
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the same things here I am creating
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another file that is file - dot txt and
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I am going to use F right to write some
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data into it and f read to read the data
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from it also buffer is clear to make
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sure that it is empty before we read the
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data
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[Music]
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fwrite function takes the data from the
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buffer and write it into the file
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remember that it will start writing from
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the starting point in the file and any
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data will be overwritten the BW is the
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pointer to the counter for the number of
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bytes written F read function will read
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the data from the file and save it in
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the buffer fill dot F size is the size
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of the data in the file B R is the
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pointer to the count variable for the
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number of bytes to read from the file
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it's time to test the code now as you
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can see along with the results from the
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previous section it gives us some new
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information also it shows that the file
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- dot txt was created and you can see
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the string that I wrote to the file -
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[Music]
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let's now see how to update an existing
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file here
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I want to update the second file to do
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so I will use the function FL seek this
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function takes two parameters the first
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is the pointer to the file and the
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second is the offset from where you want
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to start the update process here I am
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using the file size as the offset this
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means that I want it to start from the
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end and continue writing the rest of the
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reading process is same open the file
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read the data close the file let's test
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our code and check the results as you
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can see this data is up to the last
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section and this is the updated data
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this string is first printed from the
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file - and after updating the file it
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again gets printed along with the new
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string
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[Music]
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let's see how to delete the files from
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the card
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[Music]
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we are going to use f-fun link function
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which takes only one parameter and that
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is the path to the file itself if the
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results is okay it will be printed in
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the output and at last we will unmount
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the SD card it's time to test it now as
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you can see both the files are removed
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and the SD card is unmounted
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successfully let me just show you what
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happens if we try to remove files which
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are not present in my SD card
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[Music]
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note that the success message is not
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shown now and those repetitions you see
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on the top is due to the fact that the
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string is keep appending in the file
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this is it for this video guys I hope
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you understood it very well you can
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download the code from the link in the
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description leave comment in case of any
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doubt have a nice day
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[Music]
16:38
you
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