Abstract: A system and method that calculates multiple bytes of data in a single cycle. The invention uses at least two CRC circuits to calculate a CRC value for a string of data. A first CRC circuit is used for calculating multiple bytes at a time. A second CRC circuit is used for calculating a single byte. The first CRC circuit is only used when there are multiple bytes to be processed. If there are other CRC circuits, then data is directed to the appropriate CRC circuit, i.e., the CRC circuit that calculates the appropriate number of bytes, when the number of bytes remaining to be processed is less than the first CRC circuit can process. Otherwise, the data is directed to the second CRC circuit, and must be processed one byte at a time until there is no more data remaining.

Abstract: A FIFO controller circuit for interfacing data from a device running at one clock speed so that it is compatible with another device or transmission medium running at a different clock speed. A write controller is used to control the writing of data into the FIFO. The write controller is clocked at a first clock speed. A read controller is used to control the reading of data from the FIFO at a second, different clock speed. A counter is incremented when data is written to the FIFO and decremented when data is read from the FIFO. Thereby, the counter represents an amount of memory within the FIFO that is currently available. The decrement signal is generated in the first clock domain and then synchronized to the second clock domain. This provides error-free interfacing, irrespective of any phase differences existing between the two clock signals.