My story with ARM 3 beep journey, the most detailed ARM bare metal project settings

Preface

     I searched for a long time in the blog garden to find the corresponding bare metal development program of mini2440. What disappointed me was that no one gave a detailed answer to the arm part. I didn't know how to do it and how to configure it. I was very confused. So I spent nearly a week reading books, looking up information, and browsing forums. Finally, I figured out the whole process by myself! And who said that students of ARM hardware platform don't do open source? As hardware dogs, we are also happy to share our projects with you!

Personal goal setting

Use the buzzer on the mini2440 to make a call.

Prepare

Mini2440 development board, keil 4 for arm

Keil Configuration

OK, first we need to create a new project

Project->new uvision project

After writing your project name, you need to choose your own CPU

OK, we chose Samsung's S3C2440A chip

Ask you whether to add Keil to the project, we choose no and configure it ourselves

Press F2 to modify the project name

Of course, we can also right-click and select Mange Project Items to manage our project

Click OK

Our project now has a complete system

The following is to set the keil target.

Find the button

Set the ROM start address. As for why it is 0x30000000, please check the chip manual.

Setting RAM

Set the location where the file is generated. We usually put it in the Out directory

Click select folder for objects

Choose the path you want

Check the run#1 item in USER to indicate how to connect during the compilation process.

The command is as follows:

fromelf.exe --bin -o ./out/@l.bin  ./out/@l.axf

Since keil cannot generate bin files by default, you need to use the fromelf.exe tool to generate bin files

Header file introduction settings

OK, basically our project is set up!

Start your Beep journey

To operate the hardware, we must know what its circuit diagram looks like?

You see, we need to find the GPB0 port to operate the buzzer.

Then we need to operate this port, we must find its address, we go to find the MINI2440_CPU chip document

OK, we found the register of the GPB port

You have seen the GPB0 port in the chip manual, OK, then we should use the OUTPUT mode, um! Basically we have an idea.

OK, this is the register where we set the data, haha, that’s it!

Look at the blue line, English is really important! When the port is set as an output port, the GPBDAT register is set to the corresponding value.

Coding Time

OK, we have explained how to configure it very clearly above. A clear idea has been formed in our minds, and the following is how we can implement it.

Create a new blank file.

Then coded:

  AREA RESET,CODE,READONLY
    ENTRY
    LDR R1, =0x56000010 
    LDR R2, =0x1 
    STR R2, [R1]  
MainLoop
    LDR R1, =0x56000014  
    LDR R2, =0x1    
    STR R2, [R1]        
    
    LDR R1, =0xFFFFFF
Delay1 SUB R1, R1, #1
    CMP R1, #1
    BNE Delay1
    
    LDR R1, =0x56000014
    LDR R2, =0x0
    STR R2, [R1]

    LDR R1, =0xFFFFFF
Delay2 SUB R1, R1, #1
    CMP R1, #0
    BNE Delay2
    
    B MainLoop END

 Save and save our file in demo.s format

Add our files to our src directory

Add existing file to ….

Compile

See the results:

Obviously, there is no error in this project. OK, use MINItool to download the bin file in the OUT directory!