Datasheet

PIC24FJ256GB210 FAMILY
DS39975A-page 68  2010 Microchip Technology Inc.
4.2.5 EXTENDED DATA SPACE (EDS)
The enhancement of the data space in
PIC24FJ256GB210 family devices has been
accomplished by a new technique, called the Extended
Data Space (EDS).
The EDS includes any additional internal extended
data memory not accessible by the lower 32 Kbytes of
data address space, any external memory through
EPMP and the Program Space Visibility (PSV).
The extended data space is always accessed through
the EDS window, which is the upper half of data space.
The entire extended data space is organized into EDS
pages, each having 32 Kbytes of data. Mapping of the
EDS page into the EDS window is done by using the
Data Space Read register (DSRPAG<9:0>) for read
operations and Data Space Write register
(DSWPAG<8:0>) for write operations. Figure 4-4
displays the entire EDS space.
FIGURE 4-4: EXTENDED DATA SPACE
Note: Accessing Page 0 in the EDS window will
generate an address error trap as Page 0
is the base data memory (data locations,
0x0800 to 0x7FFF, in the lower data
space).
0x0000
Extended SRAM
(66 KB)
Special
Registers
30 KB Data
32 KB EDS
Window
Memory
0x8000
Program Memory
DSxPAG
= 0x001
DSxPAG
= 0x003
DSx PAG
= 0x1FF
DSRPAG
= 0x200
DSRPAG
= 0x3FF
Function
0x008000
0x00FFFE
0x000000
0x7F8001
0xFFFFFE
0x007FFE 0x7FFFFF
Internal
Program
Space
0x0800
0xFFFE
EDS Space
EPMP Memory Space
0x018000
0x0187FE
Extended
Memory
Internal
Extended
Memory
External
Memory
Access
using
EPMP
External
Memory
Access
using
EPMP
0xFF8000
DSRPAG
= 0x2FF
0x7F8000
0x7FFFFE
Access
Program
Space
Access
Program
Space
Access
DSRPAG
= 0x300
0x000001
0x007FFF
Program
Space
Access
0x01FFFE
0x018800