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Learning the STM32F4Discovery

philip-1992

Hi everyone,

 

I have an upcoming project for my finals as electrical engineer and the project consists of a design of a touch screen interface for micro controller. As I am not that familiar programming I bought the STM discovery, extention and LCD boards in order to get more familiar with the programming. I am using IAR embedded software and downloaded the examples available on this forum. I started with an example that regards the LCD the project's name is LCD_35T. Currently I am struggling understanding a few things mainly the GPIO configuration found under the stm32f4_discovery_lcd.c. I have downloaded the manual of the STM board and read the sections of GPIO (page 185-203 from the manual). However I cannot understand what each instruction is doing to each pin. Is there an explaination like a tutorial of this example?

 

Thank you in advance.

  • 0 in reply to philip-1992

    SystemInit, is in the file system_stm32f4xx.c.

    This file is essential for defining the clock source for the system core, for the timer, and the peripherals.

    ST offer an excel sheet to easily create this file. See:

    http://www.st.com/web/catalog/tools/FM147/CL1794/SC961/SS1533/PF257927

     

    You should add also system_stm32f4xx.h file.

     

    SystemInit() funtion could be called from startup file or from your main program.

     

    Startup, system, and core files are included in different ways depending on the IDE you are using. I use Coocox.

     

    Hope it helps, ask if you have any other issue about it, for me it was a little bit complicated when I was trying to figure out what was every file, and chose IDE.

     

    Regards,

    Miguel

  • 0 in reply to gihu

    Hi there I really need some guidance on this one. So far I managed to read the value from the pot, do some kind of menu which enables the user to toggle between Voltage, current and resistance. But now I noticed something due to some if statements shown here under:

    if((tst_point.x >= 3000) && (tst_point.x <= 3400))

         {

          sprintf((char*)text," Pot Value: %d Ohms",ConvertedValue);//Display the actual value of the pot on screen

         }

         else if((tst_point.x >= 1900) && (tst_point.x <= 2300))

         {

           Current = Voltage / ConvertedValue;     

           sprintf((char*)text," Current Value: %0.2f A    ",Current);//Display the actual value of the pot on screen

         }

         else if(tst_point.x <= 1200)

         {

           sprintf((char*)text," Voltage = %dV       ",Voltage);//Display the actual value of the pot on screen

         }

     

    The program loads: Mon Sep 02, 2013 15:43:28: 21480 bytes downloaded into FLASH (12.10 Kbytes/sec). The screen shows the initial menu but when I choose an option, the menu doesn't work. After a few trial and error I noticed that when I remove the 2nd if statment the program loads: Mon Sep 02, 2013 15:50:35: 16236 bytes downloaded into FLASH (13.01 Kbytes/sec) and so the touch screen works. Hence I concluded that for the program to work the maximum bytes downloaded into flash must be less than 20000 bytes. Is there a way or a setting to fix this inorder to maximize the bytes? I really do need some help to fix this as my real program will be much larger than that!!

     

    Thanks