DSPIC33FJ128MC706-I/PT Microchip Technology Inc., DSPIC33FJ128MC706-I/PT Datasheet - Page 43

• Manufacturer Part Number: DSPIC33FJ128MC706-I/PT
• Description: 16 BIT MCU/DSP 64LD 40MIPS 128KB FLASH
• Manufacturer: Microchip Technology Inc.
• Type: DSPr

Specifications of DSPIC33FJ128MC706-I/PT

• A/d Inputs: 16-Channels, 12-Bit
• Comparators: 8
• Cpu Speed: 40 MIPS
• Eeprom Memory: 0 Bytes
• Input Output: 53
• Interface: CAN/I2C/SPI/UART
• Ios: 53
• Memory Type: Flash
• Number Of Bits: 16
• Package Type: 64-pin TQFP
• Programmable Memory: 128K Bytes
• Ram Size: 16K Bytes
• Timers: 9-16-bit, 4-32-bit
• Voltage, Range: 3-3.6
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

3.2
The dsPIC33F CPU has a separate 16-bit wide data
memory space. The data space is accessed using sep-
arate Address Generation Units (AGUs) for read and
write operations. Data memory maps of devices with
different RAM sizes are shown in Figure 3-3 through
Figure 3-5.
All Effective Addresses (EAs) in the data memory space
are 16 bits wide and point to bytes within the data space.
This arrangement gives a data space address range of
64 Kbytes or 32K words. The lower half of the data
memory space (that is, when EA<15> = 0) is used for
implemented memory addresses, while the upper half
(EA<15> = 1) is reserved for the Program Space
Visibility area (see Section 3.6.3 “Reading Data From
Program Memory Using Program Space Visibility”).
dsPIC33F devices implement a total of up to 30 Kbytes
of data memory. Should an EA point to a location out-
side of this area, an all-zero word or byte will be
returned.
3.2.1
The data memory space is organized in byte address-
able, 16-bit wide blocks. Data is aligned in data
memory and registers as 16-bit words, but all data
space EAs resolve to bytes. The Least Significant
Bytes of each word have even addresses, while the
Most Significant Bytes have odd addresses.
3.2.2
To maintain backward compatibility with PICmicro
devices and improve data space memory usage
efficiency, the dsPIC33F instruction set supports both
word and byte operations. As a consequence of byte
accessibility, all effective address calculations are
internally scaled to step through word-aligned memory.
For example, the core recognizes that Post-Modified
Register Indirect Addressing mode [Ws++] will result in
a value of Ws + 1 for byte operations and Ws + 2 for
word operations.
Data byte reads will read the complete word that
contains the byte, using the LSb of any EA to determine
which byte to select. The selected byte is placed onto
the LSb of the data path. That is, data memory and reg-
isters are organized as two parallel byte-wide entities
with shared (word) address decode but separate write
lines. Data byte writes only write to the corresponding
side of the array or register which matches the byte
address.
© 2006 Microchip Technology Inc.
Data Address Space
DATA SPACE WIDTH
DATA MEMORY ORGANIZATION
AND ALIGNMENT
Preliminary
®
All word accesses must be aligned to an even address.
Misaligned word data fetches are not supported, so
care must be taken when mixing byte and word opera-
tions, or translating from 8-bit MCU code. If a mis-
aligned read or write is attempted, an address error
trap is generated. If the error occurred on a read, the
instruction underway is completed; if it occurred on a
write, the instruction will be executed but the write does
not occur. In either case, a trap is then executed, allow-
ing the system and/or user to examine the machine
state prior to execution of the address Fault.
All byte loads into any W register are loaded into the
Least Significant Byte. The Most Significant Byte is not
modified.
A sign-extend instruction (SE) is provided to allow
users to translate 8-bit signed data to 16-bit signed
values. Alternatively, for 16-bit unsigned data, users
can clear the MSb of any W register by executing a
zero-extend (ZE) instruction on the appropriate
address.
3.2.3
The first 2 Kbytes of the Near Data Space, from 0x0000
to 0x07FF, is primarily occupied by Special Function
Registers (SFRs). These are used by the dsPIC33F
core and peripheral modules for controlling the
operation of the device.
SFRs are distributed among the modules that they
control, and are generally grouped together by module.
Much of the SFR space contains unused addresses;
these are read as ‘0’. A complete listing of implemented
SFRs, including their addresses, is shown in Table 3-1
through Table 3-34.
3.2.4
The 8-Kbyte area between 0x0000 and 0x1FFF is
referred to as the Near Data Space. Locations in this
space are directly addressable via a 13-bit absolute
address field within all memory direct instructions.
Additionally, the whole data space is addressable using
MOV instructions, which support Memory Direct
Addressing mode with a 16-bit address field, or by
using Indirect Addressing mode using a working
register as an Address Pointer.
Note:
SFR SPACE
The actual set of peripheral features and
interrupts varies by the device. Please
refer to the corresponding device tables
and pinout diagrams for device-specific
information.
NEAR DATA SPACE
dsPIC33F
DS70165D-page 41