CC3220S: custom boot

Hi Andrea,

What you described should work. I use similar way with bootloader for CC3220SF (2nd stage bootlaoder is executing from XIP flash) which I written long time ago, and it works. Personally I suspect some issue with linker file, but hard to say without debugging real code... Maybe at my bootlaoder source code you find some clue.

Jan

Hi Jan,

thanks a lot for your reply.

My bootloader source code is very similar to yours (below only the procedure that load and execute the application)

#define SRAM_BASEADDR           0x20000000
#define SRAM_APP_OFFSET            0x14000

void RunFirmwareImage(unsigned long);
__asm("    .sect \".text:RunFirmwareImage\"\n"
      "    .clink\n"
      "    .thumbfunc RunFirmwareImage\n"
      "    .thumb\n"
      "RunFirmwareImage:\n"
      "    ldr    sp,[r0]\n"
      "    add    r0,r0,#4\n"
      "    ldr    r1,[r0]\n"
      "    bx     r1");

void LoadAndExecute(AppRec_t AppRec)
{
	unsigned long Token;
	long FileHandle;
	SlFsFileInfo_t FsFileInfo;

    // Get the file size using File Info structure
    if (sl_FsGetInfo(FWname[AppRec], NULL, &FsFileInfo) >= 0)
    {
        // File exist - open it
        FileHandle = sl_FsOpen(FWname[AppRec], SL_FS_READ, &Token);
        if (FileHandle > 0)
        {
            // File opened - read it into RAM
            if (sl_FsRead(FileHandle, 0, (unsigned char *)(SRAM_BASEADDR + SRAM_APP_OFFSET), FsFileInfo.Len) >= 0)
            {
                // File copied into RAM - close it
                if (sl_FsClose(FileHandle, 0, 0, 0) >= 0)
                {
                    // Eval and check CRC32
                    if (CRC32check(AppRec, (unsigned char *)(SRAM_BASEADDR + SRAM_APP_OFFSET), FsFileInfo.Len) == 0)
                    {
                        // CRC32 is correct - stop the network services
                        sl_Stop(200);
                        // Execute the application
                        RunFirmwareImage(SRAM_BASEADDR + SRAM_APP_OFFSET);
                    }
                }
            }
        }
    }
}

The only difference is the CRC32check() function, used for validate the CRC32 of the file loaded in RAM

I have 2 questions:

1. since my device is CC3220S (secure), the application (energia.bin in your example, app1.bin in my case) must be signed or I can use the "normal" bin file builded in CCS?
2. opening the map file af my application I note this:
   1. ENTRY POINT SYMBOL: "resetISR"  address: 2000cc25
   2. 2000cc24    0000001a     nortos_cc32xx.a : startup_cc32xx_ccs.oem4 (.text:resetISR)

in the line (a.), the address of resetISR it is an odd number and this address is loaded into program counter for run the application; this is correct?

Best regards

Andrea

Hi Andrea,

Answers to your questions:

1. You application cannot have header with signature at beginning of binary code. Only your bootloader should be signed against to certificate chain, because this is verified by ROM bootlaoder. You should verify if you application code does not contains this header.

2. I am sorry, but I don't understand your question. I don't use map files from TI compiler regularly. But I think similar job can do "memory allocation tool" at CCS.

I can provide example for linker files for application and bootlaoder for CC3200 device. This code I used at one of previous project. Because CC3220S and CC3200 have same way for code execution (entry point from bootlaoder 0x20004000, 256kB RAM with execution from RAM), examples should work at CC3220S as well.

bootloader:

--retain=g_pfnVectors

#define RAM_BASE 0x20004000

MEMORY
{
    SRAM_CODE (RWX) : origin = 0x20004000, length = 0x8000
    SRAM_DATA (RWX) : origin = 0x20000000, length = 0x4000
}

SECTIONS
{
    .intvecs:   > RAM_BASE
    .init_array : > SRAM_CODE
    .vtable :   > SRAM_CODE
    .text   :   > SRAM_CODE
    .const  :   > SRAM_CODE
    .cinit  :   > SRAM_CODE
    .pinit  :   > SRAM_CODE
    .data   :   > SRAM_DATA
    .bss    :   > SRAM_DATA
    .sysmem :   > SRAM_DATA
    .stack  :   > SRAM_DATA(HIGH)
}

application:

--retain=g_pfnVectors

#define RAM_BASE 0x20020000

MEMORY
{
    SRAM_DATA (RWX) : origin = 0x20000000, length = 0x20000  /* 128 KB */
    SRAM_CODE (RWX) : origin = 0x20020000, length = 0x20000  /* 128 KB */
}

SECTIONS
{
    .intvecs:   > RAM_BASE
    .init_array : > SRAM_CODE
    .vtable :   > SRAM_CODE
    .text   :   > SRAM_CODE
    .const  :   > SRAM_CODE
    .cinit  :   > SRAM_CODE
    .pinit  :   > SRAM_CODE
    .data   :   > SRAM_DATA
    .bss    :   > SRAM_DATA
    .sysmem :   > SRAM_DATA
    .stack  :   > SRAM_DATA(HIGH)
}

Jan

Hi Jan,

using the step-by-step debug in Deassembly window in CCS, I discovered that my booloader run correcly

Stack Pointer and Program counter are setted successfully and the core executes "something" (I see only the assembler code)

But, if I let the code run freely, it jump into the freertos resetISR()

So, I tried this experiment:

• I rebuilt my App1 so that the .resetVecst is mapped in 0x20004000 (entry point address)
• I removed by bootloader from flash memory and I overwrote it with the App1 (via Uniflash)

In this way, the SLB should launch App1 directly --> but not, App1 doesnt' start (!!)

The strange thing is that if I load App1 through the debugger in CCS, everything works

But I think this new problem needs a new ticket...

Best regards

Andrea