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SD CARD using SPI in STM32 || Cube-IDE || File handling || uart
Jun 26, 2019
Watch Updated Video ::: https://youtu.be/RgQt4quLh4Q
View Video Transcript
0:04
hello everybody welcome to controllers
0:08
Tech after receiving a lot of requests
0:11
on the topic today I have decided to
0:14
make a video about interfacing SD card
0:16
with stm32 using spi mode in this video
0:21
we will do some basic file handling this
0:24
includes creating opening read write
0:28
update and deleting the files other
0:32
complex functions such as directory
0:35
related and file system related
0:37
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
1:40
attention to the settings here
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[Music]
2:09
I will be using SPI one in full-duplex
2:14
master mode also I will use you up to
2:18
transmit data and rest is the usual
2:21
settings
2:24
[Music]
2:37
[Music]
2:54
[Music]
3:16
[Music]
3:45
so the project is created I will just
3:48
quickly build it once so the errors can
3:51
be avoided
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[Music]
4:03
[Music]
4:06
copy the library files that we are going
4:09
to need to the respective folders
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[Music]
4:40
we need to include this file that we
4:43
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
5:02
disk IO H file
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here we need to link the file system to
5:14
our driver just follow me
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[Music]
6:00
note that the arguments here should be
6:04
same as they are in the function to
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which this is a part of
6:25
let's build it again to check for errors
6:28
and yes we do have some errors but don't
6:31
worry we will get rid of them in our
6:33
next step in the fat FSST dot C file
6:44
make sure you define the CS port and CS
6:47
pin that you are using also the SPI
6:51
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
7:01
to define our time of functions
7:09
these timers should run independently
7:12
and that's why it's best if we define
7:15
them in the systick handler
7:29
note here all letters are gone also this
7:33
is it for the configuration let's move
7:35
to our main function now I am creating
7:49
some variables that I am going to use
7:52
these include FS for file system fill
7:56
for the file f result for storing the
7:59
result of each operation and buffer to
8:01
store the data which we can read or
8:04
write
8:09
you
8:14
be R and B W stores the counter to the
8:18
read and write in the file and at last
8:21
some variables to check the capacity of
8:24
the card
8:35
I am writing this function send UART to
8:39
make it easy to write the data to the
8:41
UART
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[Music]
8:53
[Music]
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[Music]
9:13
buf size is used to determine the size
9:16
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
9:39
okay let's start our main program by
9:43
mounting the SD card first and we are
9:46
going to use F mount function to do so
9:49
there is some verbose in case of a
9:51
failure next we are going to check the
9:54
capacity of the card we are going to use
9:57
F get free function to do so the total
10:01
size and the free space will be sent via
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the UART
10:12
now it's time to create our first file F
10:16
open function is used to open a file and
10:19
if the file does not exists it will
10:22
create it and the no puns it here F open
10:25
always does that job of creating file
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also ever read and F awright are the
10:31
access given to the file next we are
10:34
going to write some string to the file
10:36
using F port s function and then close
10:40
the file now in order to read it we need
10:52
to open it with read access and then
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copy the string from the file to the
10:57
buffer using F get s function here fill
11:00
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]
11:43
take a look at the output of the UART it
11:46
shows us the total size and the free
11:49
space in the card it also shows that the
11:52
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]
12:16
next we are going to take a look at the
12:18
F right and F read functions which do
12:22
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
12:32
data into it and f read to read the data
12:36
from it also buffer is clear to make
12:39
sure that it is empty before we read the
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data
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[Music]
12:51
fwrite function takes the data from the
12:54
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
13:15
of the data in the file B R is the
13:19
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
13:32
can see along with the results from the
13:34
previous section it gives us some new
13:37
information also it shows that the file
13:40
- dot txt was created and you can see
13:43
the string that I wrote to the file -
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[Music]
13:56
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
14:34
our code and check the results as you
14:42
can see this data is up to the last
14:44
section and this is the updated data
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this string is first printed from the
14:50
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]
15:03
let's see how to delete the files from
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the card
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[Music]
15:13
we are going to use f-fun link function
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which takes only one parameter and that
15:19
is the path to the file itself if the
15:23
results is okay it will be printed in
15:25
the output and at last we will unmount
15:28
the SD card it's time to test it now as
15:36
you can see both the files are removed
15:39
and the SD card is unmounted
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successfully let me just show you what
15:48
happens if we try to remove files which
15:51
are not present in my SD card
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[Music]
16:07
note that the success message is not
16:10
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
16:28
download the code from the link in the
16:30
description leave comment in case of any
16:33
doubt have a nice day
16:36
[Music]
16:38
you
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