CCS/TM4C1294NCPDT: Bootloader

Hi Doug,

  Even though the length was specified for 0x10000 (64kB) but the actual size of the bootloader never exceeded a few kilobytes. You can find the actual size in the map file. Below is the map file info about the size of the bootloader. The flash memory is divided into different physical sectors. Each sector is 16kB (0x4000). This is the reason the application will need to start at 0x4000 or higher rather than somewhere between 0-16kB in which case a program erase operation would have erased not just the application code but also the bootloader itself.

MODULE SUMMARY

       Module               code   ro data   rw data
       ------               ----   -------   -------
    .\boot_loader\
       bl_main.obj          1448   0         93     
       bl_packet.obj        456    8         0      
       bl_startup_ccs.obj   304    136       0      
       bl_uart.obj          176    0         0      
       bl_check.obj         92     0         0      
       bl_flash.obj         88     0         0      
    +--+--------------------+------+---------+---------+
       Total:               2564   144       93     
                                                    
       Stack:               0      0         192    
    +--+--------------------+------+---------+---------+
       Grand Total:         2564   144       285    

Great, thanks for the info Charles. Why then does the boot_serial application use 0x00010000 as the length and not 0x00004000?

Hi Doug,

The bootloader was never envisioned to occupy 64kB. It is just to inform the linker the maximum amount of flash to allocate the different sections. You can change it to 0x4000 but as is should not create any problem. Unless you instruct the linker to specifically allocate the sections to a memory range (say between 16k-64k) the linker will try to allocate starting from the 0x0.

Thanks for the info Charles!