M16C User Manual.pdf

CRC Calculation CircuitMitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTER2.10 CRC Calculation Circuit2.10.1 OverviewCyclic Redundancy Check (CRC) is a method that compares CRC code formed from transmission databy use of a polynomial generation with CRC check data so as to detect errors in transmission data. Usingthe CRC calculation circuit allows generation of CRC code. A polynomial counter is used for the polynomialgeneration of CRC_CCITT (X 16 + X 12 + X 5 + 1).(1) Registers related to CRC calculation circuitFigure 2.10.1 shows the memory map of CRC-related registers, and Figure 2.10.2 shows CRC- relatedregisters.03BC1603BD1603BE16CRC data register (CRCD)CRC input register (CRCIN)Figure 2.10.1. Memory map of CRC-related registersCRC data register(b15)(b8)b7 b0 b7 b0Symbol Address When resetCRCD 03BD16, 03BC16 IndeterminateFunctionCRC calculation result output registerValues thatcan be set000016 to FFFF16R WCRC input registerb7b0Symbo Address When resetCRCIN 03BE16 IndeterminateData input registerFunctionValues thatcan be set0016 to FF16R WFigure 2.10.2. CRC-related registers424