DSPIC30F4012 Microchip Technology Inc., DSPIC30F4012 Datasheet - Page 27

• Manufacturer Part Number: DSPIC30F4012
• Description: Dspic30f4011/4012 Enhanced Flash 16-bit Digital Signal Controller
• Manufacturer: Microchip Technology Inc.

FIGURE 3-5:
3.2
The core has two data spaces. The data spaces can be
considered either separate (for some DSP instruc-
tions), or as one unified linear address range (for MCU
instructions). The data spaces are accessed using two
Address Generation Units (AGUs) and separate data
paths.
3.2.1
The data space memory is split into two blocks, X and
Y data space. A key element of this architecture is that
Y space is a subset of X space, and is fully contained
within X space. In order to provide an apparent linear
addressing space, X and Y spaces have contiguous
addresses.
© 2007 Microchip Technology Inc.
Data
Space
EA
Note: PSVPAG is an 8-bit register containing bits <22:15> of the program space address
BSET
MOV
MOV
MOV
Upper Half of Data
Space is Mapped
into Program Space
Data Address Space
(i.e., it defines the page in program space to which the upper half of data space is being mapped).
16
DATA SPACE MEMORY MAP
CORCON,#2
#0x00, W0
W0, PSVPAG
0x9200, W0
EA<15> = 0
EA<15> = 1
DATA SPACE WINDOW INTO PROGRAM SPACE OPERATION
15
15
; PSV bit set
; Set PSVPAG register
; Access program memory location
; using a data space access
Data Space
0x8000
15
0xFFFF
0x0000
Concatenation
Address
PSVPAG
0x00
When executing any instruction other than one of the
MAC class of instructions, the X block consists of the
64-Kbyte data address space (including all Y
addresses). When executing one of the MAC class of
instructions, the X block consists of the 64-Kbyte data
address space excluding the Y address block (for data
reads only). In other words, all other instructions regard
the entire data memory as one composite address
space. The MAC class instructions extract the Y address
space from data space and address it using EAs
sourced from W10 and W11. The remaining X data
space is addressed using W8 and W9. Both address
spaces are concurrently accessed only with the MAC
class instructions.
A data space memory map is shown in Figure 3-6.
Figure 3-7 shows a graphical summary of how X and Y
data spaces are accessed for MCU and DSP
instructions.
8
dsPIC30F4011/4012
(1)
23
23
Program Space
15
Data Read
DS70135E-page 25
0
0x007FFE
0x000100
0x001200