Microchip Technology dsPIC30F - Page 64

dsPIC30F Family Reference Manual
DS70050C-page 3-4 © 2004 Microchip Technology Inc.
Figure 3-2: Data Spaces for MCU and DSP Instructions
3.1.1 Near Data Memory
An 8-Kbyte address space, referred to as near data memory, is reserved in the data memory
space between 0x0000 and 0x1FFF. Near data memory is directly addressable via a 13-bit
absolute address field within all file register instructions.
The memory regions included in the near data region will depend on the amount of data memory
implemented for each dsPIC30F device variant. At a minimum, the near data region will include
all of the SFRs and some of the X data memory. For devices that have smaller amounts of data
memory, the near data region may include all of X memory space and possibly some or all of Y
memory space. Refer to Figure 3-1 for more details.
(Y SPACE)
X SPACE
UNUSED
X SPACE
X SPACE
UNUSED
UNUSED
MCU Class Instructions (Read/Write)
Dual Source Operand DSP Instructions (Read)
Indirect EA from W10, W11
Indirect EA from W8, W9
Note: Data writes for DSP instructions consider the entire data memory as one
combined space. DSP instructions that perform an accumulator write back
use W13 as an address pointer for writes to the combined data spaces.
DSP Instructions (Write)
Y SPACE
Note: The entire 64K data space can be addressed directly using the MOV instruction.
Refer to the dsPIC30F Programmer’s Reference Manual (DS70030) for further
details.