CC78K4 Datasheet, PDF (426/523 Pages) NEC – CC78K4 Ver.2.30 or Later, C Compiler Language

CHAPTER 11 EXTENDED FUNCTIONS
(34) Flash area branch table
Flash Area Branch Table
#pragma ext_table
Caution Do not use this flash function for devices that have no flash area self-rewrite function.
Operation is not guaranteed if it is used.
This function enables the flash memory rewrite function of devices.
FUNCTIONS
• Determines the first address of the branch table for the startup routine, the interrupt function, or the function
call from the boot area to the flash area.
• The branch instruction, which is one of the branch table elements, occupies 4 bytes of area. 32 from the first
address of the branch table are reserved as dedicated interrupt functions. Ordinary functions are located after
the “first address of branch table +4 * 32.”
• The branch table occupies 4* (32 + ext_func ID max. value + 1) bytes of area. For the ext_func ID value,
refer to 11.5 (35) Function call function from the boot area to the flash area.
EFFECT
• A startup routine and interrupt function can be located in the flash area.
• A function call can be performed from the boot area to the flash area.
USAGE
• The following #pragma directive specifies the first address of the flash area branch table.
#pragma ∆ext_table ∆ branch-table-first-address
Describe the #pragma directive at the beginning of the C source.
• The following items can be described before the #pragma directive.
• Comments
• #pragma directive other than #pragma ext_func, #pragma vect with –ZF specification, #pragma
interrupt, or #pragma rtos_interrupt.
• Directives not to generate the definition/reference of variables or functions among the preprocessing
directives.
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User’s Manual U15556EJ1V0UM