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hello everyone welcome to controllers
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Tech many of you requested this so here
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we are interfacing LCD 16 by 2 with SDM
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32 but without i2c this time in parallel
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connection LCD can work in two different
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modes 8-bit and 4-bit mode in 8-bit mode
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we need to use all eight data pins and
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in 4-bit mode we can use only four data
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pins we will use 4-bit mode in this
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tutorial let's start with the cube ID
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create a new SDM 32 project
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I am using f103 c8 controller give some
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name to the project and click finish
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we have the cube MX here for the setup
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I am enabling the external crystal for
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the clock enable the serial wire debug
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we also need the delay in microseconds
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so I am using timer one for the same if
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you don't know about micro second delay
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check out the video on the top right
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corner let's set up the clock first I
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want to run the controller at maximum
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possible frequency 72 megahertz the APB
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to clock is also at 72 megahertz and
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timer 1 is connected to a PB to a
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prescaler of 72 will divide the clock to
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one megahertz input the maximum possible
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value for the ARR that is 0 cross ffff
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as it is 16-bit register as shown in
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this picture pins PA 1 to PA 7 are
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connected to the LCD we need to select
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this is it for the setup now click Save
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and the project will be generated
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here is our main dot C file first of all
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we need to include the library files you
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can get these files after you download
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the project from the link in the
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description there is nothing special in
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the header file these are the functions
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that you can use for the LCD we need to
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modify things in the LCD 1602 dot C file
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my connections is as shown in the
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picture from our s to enable pin and
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from d4 to d7 you can use any pin and
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any port for the connection just make
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sure you define them properly here
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define the timer handler that you are
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this function here is an internal
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function and it is not defined in the
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header file send to LCD is for writing
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the four bit data or command to the pins
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of the LCD it takes two parameters first
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is the useful data which is only four
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bit long and second is the RS we update
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the pins to the respective bits in the
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data variable RS must be one for sending
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data and zero for sending command once
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the data is written to the pins
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we will toggle the enable pin this will
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ensure that the data has been updated
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successfully I am keeping this 20
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microseconds delay commented out right
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we will see if it works without the
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delay or not for higher clocks this
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delay must be there if the display shows
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some weird characters try increasing or
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reducing this delay LCD send command is
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used to send the command to the LCD as
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we are only using for data pins our
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8-bit command should also be divided
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into two 4-bit commands that's why we
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need to send the command into two halves
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upper nibble and lower nibble note that
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RS is 0 to indicate that it's a command
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LCD send data is used to send the data
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to the LCD it uses the same process of
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sending the upper nibble first and then
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lower one the Rs pin must be high to
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indicate that the data is being sent LCD
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clear clears the LCD put cursor command
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is used to put the cursor at the entered
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location row can be 0 or 1 and column
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this function initializes the LCD in the
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4-bit mode these commands are written as
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per instructions in the datasheet then
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you have some display control functions
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here you can modify them if you want
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some other configuration for example if
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you want the blinking cursor use C and V
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as one in this command let's write the
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main code now first we need to include
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the header file make sure you start the
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timer before initializing the LCD now I
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am going to put the cursor at zero zero
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and send some strings to the LCD
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and then put the cursor at first row and
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zero column and then send another string
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I want to wait for three seconds and
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then clear the display inside the while
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loop this function will print the ASCII
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characters from 1 to 128 build the code
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there are no errors let's flash it
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select stm32 application click OK and
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wait for the debugger to launch
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as you can see the characters are being
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printed but quite not what we want this
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is happening due to the delay missing in
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the enable pin strobe
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let's enable the delay and flash the
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code again if you face the problem again
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try increasing or decreasing this delay
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as you can see the data is being printed
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properly let me just reset the
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controller again ASCII characters will
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continue to print from 0 to 128 every
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this is it guys I hope you understood
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the video this video was made on demand
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as I got many requests for this keep
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watching have a nice day
