DSPIC30F MICROCHIP [Microchip Technology], DSPIC30F Datasheet - Page 41

• Manufacturer Part Number: DSPIC30F
• Description: General Purpose and Sensor Families High-Performance Digital Signal Controllers
• Manufacturer: MICROCHIP [Microchip Technology]

FIGURE 3-5:
 2004 Microchip Technology Inc.
Note:
These address boundaries may vary from one
device to another.
Reset - GOTO Instruction
Alternate Vector Table
Reset - Target Address
Interrupt Vector Table
Device Configuration
Program Memory
(48K instructions)
UNITID (32 instr.)
Data EEPROM
DEVID (2)
User Flash
(Read ‘0’s)
Reserved
(4 Kbytes)
Registers
Reserved
Reserved
Reserved
Reserved
SAMPLE PROGRAM
SPACE MEMORY MAP
000000
000002
000004
00007E
000080
000084
0000FE
000100
017FFE
018000
7FEFFE
7FF000
7FFFFE
800000
8005BE
8005C0
8005FE
800600
F7FFFE
F80000
F8000E
F80010
FEFFFE
FF0000
FFFFFE
Vector Tables
Preliminary
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 X data space is used by all instructions and sup-
ports all Addressing modes. There are separate read
and write data buses. The X read data bus is the return
data path for all instructions that view data space as
combined X and Y address space. It is also the X
address space data path for the dual operand read
instructions (MAC class). The X write data bus is the
only write path to data space for all instructions.
The X data space also supports modulo addressing for
all instructions, subject to Addressing mode restric-
tions. Bit-reversed addressing is only supported for
writes to X data space.
The Y data space is used in concert with the X data
space by the MAC class of instructions (CLR, ED,
EDAC, MAC, MOVSAC, MPY, MPY.N and MSC) to
provide two concurrent data read paths. No writes
occur across the Y bus. This class of instructions dedi-
cates two W register pointers, W10 and W11, to always
address Y data space, independent of X data space,
whereas W8 and W9 always address X data space.
Note that during accumulator write back, the data
address space is considered a combination of X and Y
data spaces, so the write occurs across the X bus.
Consequently, the write can be to any address in the
entire data space.
The Y data space can only be used for the data pre-
fetch operation associated with the MAC class of
instructions. It also supports modulo addressing for
automated circular buffers. Of course, all other instruc-
tions can access the Y data address space through the
X data path as part of the composite linear space.
The boundary between the X and Y data spaces is
defined as shown in Figure 3-8 and is not user pro-
grammable. Should an EA point to data outside its own
assigned address space, or to a location outside phys-
ical memory, an all zero word/byte will be returned. For
example, although Y address space is visible by all
non-MAC instructions using any Addressing mode, an
attempt by a MAC instruction to fetch data from that
space using W8 or W9 (X space pointers) will return
0x0000.
Data Address Space
DATA SPACES
dsPIC30F
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