17.2.11 Get CRC (GET_CRC) Command

GET_CRC calculates the CRC of the buffer from the specified address to the specified length, using the table look-up method. The CRC details are as follows:
  • CRC-CCITT, 16-bit
  • Polynomial: X^16+X^12+X^5+1, hex 0x00011021
  • Seed: 0xFFFF
  • MSB shifted in first
Note:

  1. In the response, only the CRC LSb, 16 bits are valid.

  2. The PE will automatically determine if the hardware CRC is available and uses it by default. The hardware CRC is not used on PIC32MX1XX/2XX devices.

Figure 17-20. Get CRC (GET_CRC) Command
Table 17-12. Get CRC (GET_CRC) Format
FieldDescription
Op code0x8
OperandNot used
AddressAddress where to start calculating the CRC
LengthLength of buffer on which to calculate the CRC, in number of bytes
Expected Response (2 words):
Figure 17-21. Get CRC (GET_CRC) Response