DSPIC33FJ128MC506-I/PT Microchip Technology Inc., DSPIC33FJ128MC506-I/PT Datasheet - Page 71

• Manufacturer Part Number: DSPIC33FJ128MC506-I/PT
• Description: DSP, 16-Bit, 128KB Flash, 8KB RAM, 53 I/O, TQFP-64
• Manufacturer: Microchip Technology Inc.
• Type: DSPr

Specifications of DSPIC33FJ128MC506-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/USART
• Ios: 53
• Memory Type: Flash
• Number Of Bits: 16
• Package Type: 64-pin TQFP
• Programmable Memory: 128K Bytes
• Ram Size: 8K Bytes
• Timers: 9-16-bit, 4-32-bit
• Voltage, Range: 3-3.6
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

advisable to use W14 or W15 for Modulo Addressing
since these two registers are used as the Stack Frame
Pointer and Stack Pointer, respectively.
In general, any particular circular buffer can only be
configured to operate in one direction as there are
certain restrictions on the buffer start address (for incre-
menting buffers), or end address (for decrementing
buffers), based upon the direction of the buffer.
The only exception to the usage restrictions is for buff-
ers which have a power-of-2 length. As these buffers
satisfy the start and end address criteria, they may
operate in a bidirectional mode (i.e., address boundary
checks will be performed on both the lower and upper
address boundaries).
3.4.1
The Modulo Addressing scheme requires that a starting
and ending address be specified and loaded into the
16-bit Modulo Buffer Address registers: XMODSRT,
XMODEND,
Table 3-1).
FIGURE 3-7:
© 2007 Microchip Technology Inc.
Note:
Address
0x1100
0x1163
Byte
START AND END ADDRESS
Y space Modulo Addressing EA calcula-
tions assume word sized data (LSb of
every EA is always clear).
YMODSRT
Start Addr = 0x1100
End Addr = 0x1163
Length = 0x0032 words
MODULO ADDRESSING OPERATION EXAMPLE
and
YMODEND
MOV
MOV
MOV
MOV
MOV
MOV
MOV
MOV
DO
MOV
AGAIN: INC
(see
Preliminary
#0x1100, W0
W0, XMODSRT
#0x1163, W0
W0, MODEND
#0x8001, W0
W0, MODCON
#0x0000, W0
#0x1110, W1
AGAIN, #0x31
W0, [W1++]
W0, W0
The length of a circular buffer is not directly specified. It
is determined by the difference between the correspond-
ing start and end addresses. The maximum possible
length of the circular buffer is 32K words (64 Kbytes).
3.4.2
The Modulo and Bit-Reversed Addressing Control
register, MODCON<15:0>, contains enable flags as well
as a W register field to specify the W Address registers.
The XWM and YWM fields select which registers will
operate with Modulo Addressing. If XWM = 15, X RAGU
and X WAGU Modulo Addressing is disabled. Similarly, if
YWM = 15, Y AGU Modulo Addressing is disabled.
The X Address Space Pointer W register (XWM), to
which Modulo Addressing is to be applied, is stored in
MODCON<3:0> (see Table 3-1). Modulo Addressing is
enabled for X data space when XWM is set to any value
other than ‘15’ and the XMODEN bit is set at
MODCON<15>.
The Y Address Space Pointer W register (YWM) to
which Modulo Addressing is to be applied is stored in
MODCON<7:4>. Modulo Addressing is enabled for Y
data space when YWM is set to any value other than
;set modulo start address
;set modulo end address
;enable W1, X AGU for modulo
;W0 holds buffer fill value
;point W1 to buffer
;fill the 50 buffer locations
;fill the next location
;increment the fill value
W ADDRESS REGISTER
SELECTION
dsPIC33F
DS70165E-page 69