MA330028 Microchip Technology, MA330028 Datasheet - Page 370

• Manufacturer Part Number: MA330028
• Description: Daughter Cards & OEM Boards dsPIC33EP64MC504 PIM
• Manufacturer: Microchip Technology

Specifications of MA330028

• Rohs: yes
• Product: Daughter Cards
• Core: dsPIC
• Description/function: Plug-in-module with dsPIC33EP64MC504 device for use with DM330021 and DM330023 motor control development board
• Interface Type: CAN, I2C, SPI
• Operating Supply Voltage: 3 to 3.6 V
• Tool Is For Evaluation Of: dsPIC33EP64MC504
• For Use With: DM330021, DM330023

Note that the appropriate positions are set to ‘1’ to
26.1
The CRC module can be programmed for CRC
polynomials of up to the 32nd order, using up to 32 bits.
Polynomial length, which reflects the highest exponent
in the equation, is selected by the PLEN<4:0> bits
(CRCCON2<4:0>).
The CRCXORL and CRCXORH registers control which
exponent terms are included in the equation. Setting a
particular bit includes that exponent term in the
equation; functionally, this includes an XOR operation
on the corresponding bit in the CRC engine. Clearing
the bit disables the XOR.
For example, consider two CRC polynomials, one a 16-
bit equation and the other a 32-bit equation:
To program these polynomials into the CRC generator,
set the register bits as shown in
indicate that they are used in the equation (for example,
X26 and X23). The 0 bit required by the equation is
always XORed; thus, X0 is a don’t care. For a poly-
nomial of length N, it is assumed that the Nth bit will
always be used, regardless of the bit setting. Therefore,
for a polynomial length of 32, there is no 32nd bit in the
CRCxOR register.
TABLE 26-1:
DS70657E-page 370
x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7
PLEN<4:0>
X<31:16>
X<15:0>
CRC Control
Bits
Overview
+ x5 + x4 + x2 + x + 1
16 AND 32-BIT POLYNOMIAL
x16 + x12 + x5 + 1
CRC SETUP EXAMPLES FOR
0000 0000
0000 000x
0001 0000
0010 000x
Polynomial
01111
16-bit
and
Bit Values
Table
26-1.
Polynomial
0000 0100
1100 0001
0001 1101
1011 011x
11111
32-bit
Preliminary
26.2
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 link, contains the latest updates
and additional information.
26.2.1
• Section 27. “Programmable Cyclic Redundancy
• Code Samples
• Application Notes
• Software Libraries
• Webinars
• All related dsPIC33E/PIC24E Family Reference
• Development Tools
Note:
Check (CRC)” (DS70346)
Manuals Sections
Programmable CRC Resources
In the event you are not able to access the
product page using the link above, enter
this URL in your browser:
http://www.microchip.com/wwwproducts/
Devices.aspx?dDocName=en555464
KEY RESOURCES
© 2011-2012 Microchip Technology Inc.