Maxim Integrated DS4830 Optical Microcontroller - Manual (Page 222)

DS4830 User’s Guide
222
25.3
– Data Transfer Functions
The DS4830 cannot access data from the same memory segment that is currently being used for instructions. For
example, when instructions are executing from FLASH, data in FLASH cannot be accessed. The following utility ROM
functions can be used to transfer data from one memory segment to another. For example, if data in FLASH needs to be
copied to SRAM, one of these ROM functions can be called to do this transfer. This is useful when code is executing
from FLASH and access to lookup tables or non-volatile data that is stored in FLASH is required. These functions can
also be used by code running from SRAM to read data that is stored in SRAM.
Since these functions are executed from utility ROM, addresses must be specified correctly to point to t h e in t e n d ed
memory segments. When executing from utility ROM, the memory map is illustrated in Figure 25-1. For example, data
located at word address 0100h in the FLASH must be accessed at word address 8100h (or byte address 8200h) when
using any of the functions listed in the following sections.
Figure 25-1 : Memory Map when Executing from Utility ROM