Dynamically configurable memory system having a programmable controller including a frequency multiplier to maintain memory timing resolution for different bus speeds

摘要

A memory system includes a memory and a controller coupled to the memory and a system bus. The controller is configured to receive a bus clock and control signals over the system bus and to provide memory control signals with a predetermined timing resolution to the memory. The controller includes a bus clock frequency multiplication circuit for generating an internal clock signal which is used to generate the memory control signals, and a programmable timing register for storing timing intervals of the memory control signals. The bus frequency multiplication circuit generates the internal clock signal by multiplying the frequency of the bus clock by a bus frequency multiplication factor which is selectively chosen to set the predetermined timing resolution for the memory control signals to a nearly constant value independent of the frequency of the bus clock. The bus frequency multiplication circuit may comprise a phase locked loop.