M16C65 Datasheet, PDF (723/829 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/60

Under development
M16C/65 Group
Preliminary Specification
This is a preliminary specification and is subject to change.
29. CRC Calculator
29. CRC Calculator
29.1 Introduction
The CRC (Cyclic Redundancy Check) calculator detects errors in data blocks. This CRC calculator is
enhanced by additional feature, CRC snoop, in order to monitor reads from and writes to a certain SFR
address, and perform CRC calculations automatically on the data read from and data written to the
aforementioned SFR address. Figure 29.1 shows CRC Calculator Block Diagram. Figure 29.2 shows CRC
Operation (CRC-CCITT).
Table 29.1 CRC Calculator Specification
Item
Operation polynomial
Selectable function
Specification
CRC-CCITT (X¹⁶ + X¹² + X⁵ + 1) or CRC-16 (X¹⁶ + X¹⁵ + X² + 1)
• MSB/LSB selectable
• CRC snoop
High-order bit of data bus
Low-order bit of data bus
8 low-order bits
CRCD register (16)
8 high-order bits
(03BDh, 03BCh)
CRC generator
X¹⁶+X¹²+X⁵+1 or X¹⁶+X¹⁵+X²+1
CRCIN register (8)
(03BEh)
Address bus
Figure 29.1 CRC Calculator Block Diagram
CRC snoop block
SFR to snoop
=?
Snoop
enabled
REJ09B0484-0030 Rev.0.30 Sep 09, 2008
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