1 Reply Latest reply on Apr 21, 2019 11:33 PM by GeonaP_26

    Checsum exclude section regarding example


      referring to this older post: How do I locate a variable in the checksum exclude region for a bootloadable app




      what is 0x7ff00?

      How does it correlate to the other numbers in the example (128, 254..)?

      How does it correlate to the example in the document?


        • 1. Re: Checsum exclude section regarding example

          Bootloader and bootloadable project reserve the last flash row for metadata. The 128 bytes of checksum exclude memory section will be placed from the second last flash row. CY8C4245AXI has 32kB flash with each flash row of size 128 bytes. rom (rx) is from 0 to 0x00007FFF. Hence, second last flash row starts from 0x00007F00. You can refer to the .map file for more details;


                          0x00007f00       0x80
                          0x00007f00       0x80 .\CortexM0\ARM_GCC_541\Debug\main.o
                          0x00007f00                byteArray
                          0x00000080                cy_checksum_exclude_size = (CY_APPL_LOADABLE == 0x1)?SIZEOF (.cy_checksum_exclude):0x0
                          0x00000001                ASSERT ((cy_checksum_exclude_size <= CY_CHECKSUM_EXCLUDE_SIZE), CY_BOOT: Section .cy_checksum_exclude size exceedes specified limit.)
                          0xf0000000                cyloadermeta_start = (cy_project_type_bootloader || cy_project_type_app_for_stack_and_copier)?(LENGTH (rom) - CY_METADATA_SIZE):0xf0000000


          Suppose you configure 256 bytes of checksum exclude size, it will start from 0x00007E80.