STM32F7 Discovery Board STemWin examples

stm32stm32f7

I've tried compiling the included ticker example with the STemWin_HelloWorld project included in STM32CubeF7. Functionally, it works OK but the draws seem to be corrupted.

Take a look at the video I've uploaded onto YouTube:

I suspect it as something to do with the configuration of the memory but I cannot be sure. This was compiled using SW4STM32.

Best Answer

Answer is taken from the ST forum here.

Turns out you have to disable caching by commenting out the line in the main function:

CPU_CACHE_Enable();

Related Solutions

Electronic – Which camera module will interface with STM32F7 Disco board

From STM32F7 User Manual, page 16:

A connector P1 with the DCMI signals is available to connect a camera module such as STM32F4DIS-CAM (ST order code)

So the camera module that recommended by manufacturer is STM32F4DIS-CAM, see this ST page, Digikey, or other distributors.

For your questions:

Could the OV2640 be adapted for this?

I think the answer is Yes. There are many projects on the web that connecting OV2640 to STM32 family module, for example this with DCMI or this without DCMI.

Electronic – Writing STM32F7 code without external files

This is a stackoverflow question not an electrical engineering question.

The STM32F7 has a Cortex-M7, which like the m4 and m3 is ARMv7-M based. thumb+thumb2 extensions for the instruction set, boots the same, etc.

The ST documentation should show you the register list for the chip. You can create a single file header file from that. If you are looking for someone to search the net for you, this is not the place, nor is stack overflow.

tons of bare metal examples out there to work from, start with any cortex-m example to see how that is done. One asm file and one C file are all yeed bare minimum (probably could do one C file, but safer with a handful of lines of asm for the vector table).

for example

flash.s

.thumb
.thumb_func
.global _start
_start:
stacktop: .word 0x20001000
.word reset
.word hang
.word hang
.word hang
.word hang
.word hang
.word hang
.word hang
.word hang
.word hang
.word hang
.word hang
.word hang
.word hang
.word hang
.thumb_func
reset:
    bl main
    b hang
.thumb_func
hang:   b .
.align
.thumb_func
.globl PUT32
PUT32:
    str r1,[r0]
    bx lr
.thumb_func
.globl GET32
GET32:
    ldr r0,[r0]
    bx lr
.end

test.c

extern void PUT32 ( unsigned int, unsigned int );
extern unsigned int GET32 ( unsigned int );


#define STK_CSR 0xE000E010
#define STK_RVR 0xE000E014
#define STK_CVR 0xE000E018
#define STK_MASK 0x00FFFFFF

static int delay ( unsigned int n )
{
    unsigned int ra;

    while(n--)
    {
        while(1)
        {
            ra=GET32(STK_CSR);
            if(ra&(1<<16)) break;
        }
    }
    return(0);
}

int main ( void )
{
    PUT32(STK_CSR,4);
    PUT32(STK_RVR,1000000-1);
    PUT32(STK_CVR,0x00000000);
    PUT32(STK_CSR,5);

    delay(100);


    return(0);
}

flash.ld

MEMORY
{
    ram : ORIGIN = 0x08000000, LENGTH = 0x1000
}

SECTIONS
{
    .text : { *(.text*) } > ram
    .rodata : { *(.rodata*) } > ram
    .bss : { *(.bss*) } > ram
}

You dont need the linker file you can do something like -Ttext=0xaddress instead of a linker script.

arm-none-eabi-as --warn --fatal-warnings -mcpu=cortex-m0 flash.s -o flash.o
arm-none-eabi-gcc -Wall  -O2 -nostdlib -nostartfiles -ffreestanding -mthumb -c test.c -o test.gcc.thumb.o
arm-none-eabi-ld -o test.gcc.thumb.flash.elf -T flash.ld flash.o test.gcc.thumb.o
arm-none-eabi-objdump -D test.gcc.thumb.flash.elf > test.gcc.thumb.flash.list
arm-none-eabi-objcopy test.gcc.thumb.flash.elf test.gcc.thumb.flash.bin -O binary

Yes I know that says cortex-m0 instead of -m7, borrowed from an example m0 gives you just thumb no or few thumb2 extensions, should work on all cortex-ms.

disassembly of above.

Disassembly of section .text:

08000000 <_start>:
 8000000:   20001000    andcs   r1, r0, r0
 8000004:   08000041    stmdaeq r0, {r0, r6}
 8000008:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 800000c:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 8000010:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 8000014:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 8000018:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 800001c:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 8000020:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 8000024:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 8000028:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 800002c:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 8000030:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 8000034:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 8000038:   08000047    stmdaeq r0, {r0, r1, r2, r6}
 800003c:   08000047    stmdaeq r0, {r0, r1, r2, r6}

08000040 <reset>:
 8000040:   f000 f806   bl  8000050 <main>
 8000044:   e7ff        b.n 8000046 <hang>

08000046 <hang>:
 8000046:   e7fe        b.n 8000046 <hang>

08000048 <PUT32>:
 8000048:   6001        str r1, [r0, #0]
 800004a:   4770        bx  lr

0800004c <GET32>:
 800004c:   6800        ldr r0, [r0, #0]
 800004e:   4770        bx  lr

08000050 <main>:
 8000050:   b570        push    {r4, r5, r6, lr}
 8000052:   2104        movs    r1, #4
 8000054:   480e        ldr r0, [pc, #56]   ; (8000090 <main+0x40>)
 8000056:   f7ff fff7   bl  8000048 <PUT32>
 800005a:   490e        ldr r1, [pc, #56]   ; (8000094 <main+0x44>)
 800005c:   480e        ldr r0, [pc, #56]   ; (8000098 <main+0x48>)
 800005e:   f7ff fff3   bl  8000048 <PUT32>
 8000062:   2100        movs    r1, #0
 8000064:   480d        ldr r0, [pc, #52]   ; (800009c <main+0x4c>)
 8000066:   f7ff ffef   bl  8000048 <PUT32>
 800006a:   2480        movs    r4, #128    ; 0x80
 800006c:   2105        movs    r1, #5
 800006e:   4808        ldr r0, [pc, #32]   ; (8000090 <main+0x40>)
 8000070:   f7ff ffea   bl  8000048 <PUT32>
 8000074:   2564        movs    r5, #100    ; 0x64
 8000076:   0264        lsls    r4, r4, #9
 8000078:   4805        ldr r0, [pc, #20]   ; (8000090 <main+0x40>)
 800007a:   f7ff ffe7   bl  800004c <GET32>
 800007e:   4220        tst r0, r4
 8000080:   d0fa        beq.n   8000078 <main+0x28>
 8000082:   3d01        subs    r5, #1
 8000084:   2d00        cmp r5, #0
 8000086:   d1f7        bne.n   8000078 <main+0x28>
 8000088:   2000        movs    r0, #0
 800008a:   bc70        pop {r4, r5, r6}
 800008c:   bc02        pop {r1}
 800008e:   4708        bx  r1
 8000090:   e000e010    and lr, r0, r0, lsl r0
 8000094:   000f423f    andeq   r4, pc, pc, lsr r2  ; <UNPREDICTABLE>
 8000098:   e000e014    and lr, r0, r4, lsl r0
 800009c:   e000e018    and lr, r0, r8, lsl r0

Normally we boot from address 0 but the STM32 parts or at least the latest one I played with and at least one of the STM32F7's (you didnt specify which one you were interested in) has the user flash start at 0x08000000 so -Ttext=0x08000000 (gnu gets a little funny with this command line approach and can put gaps of dead space, I prefer the linker script).

If you are using another toolchain (gnu is always available and free and tons of online support) then the asm syntax is likely different. Linker scripts are likely a lot different.

and yes my simple example uses a cortex periheral set of registers not any of the chip vendor (st in this case) specific addresses. the stm32f7 I am looking at for example RCC starts at address 0x40023800

so perhaps you might want to create this

#define RCC_APB1ENR (0x40023800+0x40)

Best Answer

Related Solutions

Electronic – Which camera module will interface with STM32F7 Disco board

Electronic – Writing STM32F7 code without external files

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