TDGL007 Microchip Technology, TDGL007 Datasheet - Page 68

• Manufacturer Part Number: TDGL007
• Description: Development Boards & Kits - PIC / DSPIC DIGILENT CEREBOT MC7 MOTOR CONTROL BRD
• Manufacturer: Microchip Technology

Specifications of TDGL007

• Product: Development Boards
• Interface Type: CAN, I2C
• Operating Supply Voltage: 5 V

dsPIC33FJXXXMCX06A/X08A/X10A
4.4.3
Modulo Addressing can be applied to the Effective
Address (EA) calculation associated with any W
register. It is important to realize that the address
boundaries check for addresses less than or greater
than the upper (for incrementing buffers) and lower (for
decrementing buffers) boundary addresses (not just
equal to). Address changes may, therefore, jump
beyond boundaries and still be adjusted correctly.
4.5
Bit-Reversed Addressing mode is intended to simplify
data reordering for radix-2 FFT algorithms. It is
supported by the X AGU for data writes only.
The modifier, which may be a constant value or register
contents, is regarded as having its bit order reversed. The
address source and destination are kept in normal order;
thus, the only operand requiring reversal is the modifier.
4.5.1
Bit-Reversed Addressing mode is enabled when the
following conditions exist:
1.
2.
3.
DS70594C-page 68
Note:
The BWM bits (W register selection) in the
MODCON register are any value other than 15
(the
Bit-Reversed Addressing).
The BREN bit is set in the XBREV register.
The addressing mode used is Register Indirect
with Pre-Increment or Post-Increment.
Bit-Reversed Addressing
stack
MODULO ADDRESSING
APPLICABILITY
The modulo corrected Effective Address
is written back to the register only when
Pre-Modify or Post-Modify Addressing
mode is used to compute the Effective
Address. When an address offset (e.g.,
[W7+W2]) is used, Modulo Address
correction is performed but the contents of
the register remain unchanged.
BIT-REVERSED ADDRESSING
IMPLEMENTATION
cannot
be
accessed
using
If the length of a bit-reversed buffer is M = 2
the last ‘N’ bits of the data buffer start address must
be zeros.
XB<14:0> is the Bit-Reversed Address modifier, or
‘pivot point,’ which is typically a constant. In the case of
an FFT computation, its value is equal to half of the FFT
data buffer size.
When enabled, Bit-Reversed Addressing is only
executed for Register Indirect with Pre-Increment or
Post-Increment Addressing and word-sized data
writes. It will not function for any other addressing
mode or for byte-sized data; normal addresses are
generated instead. When Bit-Reversed Addressing is
active, the W Address Pointer is always added to the
address modifier (XB) and the offset associated with
the Register Indirect Addressing mode is ignored. In
addition, as word-sized data is a requirement, the LSb
of the EA is ignored (and always clear).
If Bit-Reversed Addressing has already been enabled
by setting the BREN bit (XBREV<15>), then a write to
the XBREV register should not be immediately followed
by an indirect read operation using the W register that
has been designated as the Bit-Reversed Pointer.
Note:
Note:
All bit-reversed EA calculations assume
word-sized data (LSb of every EA is
always clear). The XB value is scaled
accordingly to generate compatible (byte)
addresses.
Modulo Addressing and Bit-Reversed
Addressing
together. In the event that the user
attempts to do so, Bit-Reversed Address-
ing will assume priority for the X WAGU,
and X WAGU Modulo Addressing will be
disabled. However, Modulo Addressing will
continue to function in the X RAGU.
© 2011 Microchip Technology Inc.
should
not
be
enabled
N
bytes,