Memory controller for reading data from synchronous RAM
US5577236A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 1994 |
| Grant date | Nov 19, 1996 |
| Priority date | — |
| Expiry date | Dec 30, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C7/1072
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A memory controller reads data from a memory bank of synchronous RAM during a small and variable data valid window, by compensating for delays in receiving the data caused by memory loading, chip and card manufacturing process variations, and the like. The memory controller includes a system clock driver to supply the memory bank with a clock reference signal. A sampling clock provides an assortment of sampling clock signals duplicative of the system clock signal, with various delays. A command driver initiates Read operations in the memory bank by relaying Read command signals to the memory bank. In response to the level of memory loading, such as the number of memory modules present in the memory bank, a clock selector directs a selected one of the sampling clock signals to a delay module, which replicates any delay the system clock driver may have. If desired, an additional, user-selectable supplementary delay unit may be used to increase the delay provided by the delay module, thereby increasing or offsetting the delay of the selected sampling clock signal. The delay module provides a delayed clock signal to synchronize receipt of Read data signals from the memory bank at a clo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.