10.2.1. ROM at 0x0

The simplest layout is to locate the application in ROM at address 0 in the memory map. The application can then branch to the real entry point when it executes its first instruction (at the reset vector at address 0x0).

Figure 10.1. Example of a system with ROM at 0x0

However, there are disadvantages with this layout. ROM is typically narrow and slow (requires wait states to access it). This slows down the handling of processor exceptions (especially interrupts) through the vector table. Also, if the vector table is in ROM, it cannot be modified by the code.

For more information on exception handling, see Chapter 9 Handling Processor Exceptions.

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