Maxim Integrated MAXQ610 - Manual (Page 13)

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MAXQ610 User’s Guide
2.5.1 Memory Mapping Into Data Space
The MAXQ610 maps program memory into data space from 0000h to 7FFFh . The selection of physical program
memory page or pages to be logically mapped to data space is determined by the CDA1 and CDA0 bits, as shown in
Table 2-2 . Note that CDA1 is fixed at 0 .
Figure 2-3 summarize the default memory maps for this memory structure . The WBSn bits of the MAXQ610 default to
word access mode (WBSn = 1) .
The upper half of the data memory map (8000h to FFFFh) is the logical area for the utility ROM when accessed as
data . Executing code from the utility ROM allows the user to map the program memory to 8000h to FFFFh by properly
selecting the CDA bits .
Figure 2-4 and 2-5 illustrate the effects of the CDA bits .
Figure 2-3. MAXQ610 Memory Map (64KB Program Space)
Table 2-2. CDA Bits to Access Program Space as Data
PROGRAM
SPACE
87FFh
7FFFh
0000h
8000h
2K x 16
UTILITY ROM
2K x 8
DATA SRAM
1K x 16
DATA SRAM
32K x 16
PROGRAM FLASH
OR
MASKED ROM
DATA SPACE
(BYTE MODE)
DATA SPACE
(WORD MODE)
0000h
07FFh
0000h
03FFh
CDA[1:0] SELECTED PAGE IN BYTE MODE SELECTED PAGE IN WORD MODE
00 P0 P0 and P1
01 P1 P0 and P1