Microchip Technology MA330016 Data Sheet
© 2007-2011 Microchip Technology Inc.
DS70290J-page 33
dsPIC33FJ32GP202/204 and dsPIC33FJ16GP304
4.2.5
X AND Y DATA SPACES
The core has two data spaces, X and Y. These data
spaces can be considered either separate (for some
DSP instructions), 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. This feature allows certain
instructions to concurrently fetch two words from RAM,
thereby enabling efficient execution of DSP algorithms
such as Finite Impulse Response (FIR) filtering and
Fast Fourier Transform (FFT).
The X data space is used by all instructions and
supports all addressing modes. X data space has
separate read and write data buses. The X read data
bus is the read data path for all instructions that view
data space as combined X and Y address space. It is
also the X data prefetch path for the dual operand DSP
instructions (MAC class).
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.
Both the X and Y data spaces support Modulo
Addressing mode for all instructions, subject to
addressing mode restrictions. Bit-Reversed Addressing
mode is only supported for writes to X data space.
All data memory writes, including in DSP instructions,
view data space as combined X and Y address space.
The boundary between the X and Y data spaces is
device-dependent and is not user-programmable.
All effective addresses are 16 bits wide and point to
bytes within the data space. Therefore, the data space
address range is 64 Kbytes, or 32K words, though the
implemented memory locations vary by device.
spaces can be considered either separate (for some
DSP instructions), 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. This feature allows certain
instructions to concurrently fetch two words from RAM,
thereby enabling efficient execution of DSP algorithms
such as Finite Impulse Response (FIR) filtering and
Fast Fourier Transform (FFT).
The X data space is used by all instructions and
supports all addressing modes. X data space has
separate read and write data buses. The X read data
bus is the read data path for all instructions that view
data space as combined X and Y address space. It is
also the X data prefetch path for the dual operand DSP
instructions (MAC class).
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.
Both the X and Y data spaces support Modulo
Addressing mode for all instructions, subject to
addressing mode restrictions. Bit-Reversed Addressing
mode is only supported for writes to X data space.
All data memory writes, including in DSP instructions,
view data space as combined X and Y address space.
The boundary between the X and Y data spaces is
device-dependent and is not user-programmable.
All effective addresses are 16 bits wide and point to
bytes within the data space. Therefore, the data space
address range is 64 Kbytes, or 32K words, though the
implemented memory locations vary by device.
4.3
Program Memory Resources
Many useful resources are provided on the main prod-
uct page of the Microchip web site for the devices listed
in this data sheet. This product page, which can be
accessed using this
uct page of the Microchip web site for the devices listed
in this data sheet. This product page, which can be
accessed using this
, contains the latest updates
and additional information.
4.3.1
KEY RESOURCES
• Section 4. “Program Memory” (DS70202)
• Code Samples
• Application Notes
• Software Libraries
• Webinars
• All related dsPIC33F/PIC24H Family Reference
• Code Samples
• Application Notes
• Software Libraries
• Webinars
• All related dsPIC33F/PIC24H Family Reference
Manuals Sections
• Development Tools
Note:
In the event you are not able to access
the product page using the link above,
enter this URL in your browser:
the product page using the link above,
enter this URL in your browser: