TMS570LS1224: CAN Bootloader - Application Side Example to Modify "Magic Number"

Hi Tom,

My understanding is that the application has been programmed to flash successfully. But your application wants to write new magic word to 0x10000, so the bootloader can update the application again. 

What is the value of the ESM status register for ESM group 3?

BTW, You can pull one GPIO (example uses GIOA.7) low to force the bootloader to update the application. 

I suggest another way to store the magic word:

1. Use the last flash sector if it is not used by your application code

2. use bank7 as EEPROM to store the magic word. 

I think I tried using the FEE library, but realized I could only write to Bank 7, not 0x10000. I'll try changing the APP_STATUS_ADDRESS location to the beginning of Bank 7 in the bootloader, and using FEE in my application. We need to store some persistent state anyway, and I'd planned to use FEE for that.

RE: using a GIO pin to initiate update - the board will be in a remote, unattended location. I considered using a latch to set an unused pin low prior to resetting the MCU, but that started adding parts and more failure modes. Still keeping it as an option.

Thank you for the prompt response.

- Tom

Thanks Tom.

When the magic numbers are written by the bootloader, their ECC values are also programmed to ECC space. If you want to toggle one bit of the magic number from "1" to "0", the corresponding ECC value is programmed automatically at the same time, but if the previous ECC value is "0", the ECC will not be changed. This means you have wrong ECC value for the new magic number. This is why I don't suggest to write magic numbers without erase them.

My initial naive change in bl_config.h:

#define APP_STATUS_ADDRESS      0xF0200000 //0x00010000

results in the bootloader hanging in Fapi_UpdateStatusProgram() in bl_flash.c:

uint32_t Fapi_UpdateStatusProgram(uint32_t Flash_Start_Address, uint32_t Data_Start_Address, uint32_t Size_In_Bytes)
{
	register uint32_t src = Data_Start_Address;
	register uint32_t dst = Flash_Start_Address;
	unsigned int bytes;

	if (Size_In_Bytes < 16)
		bytes = Size_In_Bytes;
	else
		bytes = 16;

	Fapi_issueProgrammingCommand((uint32_t *)dst,
									 (uint8_t *)src,
									 (uint32_t) bytes,
									 0,
									 0,
									 Fapi_AutoEccGeneration);

 	while( Fapi_checkFsmForReady() == Fapi_Status_FsmBusy );
        while(FAPI_GET_FSM_STATUS != Fapi_Status_Success); // <-- hangs here
        return (0);
} 

I may be missing a required change to bl_link.cmd or some other file to allow access to Bank 7, but I haven't needed to modify a linker file before.

- Tom

Quick update - I am able to write the magic word to the first four bytes of Bank 7 (EEPROM) in the bootloader. However, I still cannot write to that location in my application using either TI_Fee_WriteAsync() or TI_Fee_WriteSync() or using the F021 "native" API.

Went back to looking at the TI FEE example, and that doesn't seem to be working properly now either. I made some changes to the linker file to make the binary loadable with the bootloader, which may be causing issues.

I may have to come back to this in a couple of weeks since I may not be able to access the hardware for a while.

- Tom

Hello Tom,

The EEPROM works in different way from the main flash. If magic words is different magic words defined in bootloader, the magic words will be written to different locations in EEPROM. Reading is to read the block number rather than the physical flash address.