摘要:
A buffer IC includes two FIFO buffers accessible in a triple-bus configuration including a bi-directional port, an input port, and an output port. Each of the ports uses a fall-through timing which facilitates interconnection of similar buffer ICs into a chain to expand the depth of a FIFO buffer. Typically, the input and output ports have a data width that differs from the data width of the bi-directional bus the FIFO buffers perform bus matching. One type of bus matching collects data values from the smaller width port to form larger width values for output from the larger port. Another type of bus matching splits data values from the larger width port to form data values for output from the smaller port.
摘要:
A clock signal generator or frequency multiplier generates an output signal having a frequency which is a non-integer multiple of an input signal frequency. One clock signal generator contains one or more shift registers. A signal generated from a logical combination of bits from the shift registers transitions from high to low or low to high as values in the shift registers shift. The transitions have a pattern which repeats each time values in the shift registers return to their initial states and the initial states stored in the shift registers control the number of transitions per repetition. The frequency of the combined signal is the frequency of the input signal times the ratio of the number of transitions per repetition to the number of shifts per repetition. One embodiment of the invention provides a 1.33x multiple of an input clock signal. Using a 1.33x multiple of a nominally highest frequency input clock signal from a set of input clock signals provides an output clock signal having a frequency greater than any input clock signal in the set even if the frequencies of the input clock signals vary from their nominal frequencies by up to 10%.