An innovative design of the DDR/DDR2 SDRAM compatible controller

With the rapid increases of computer performance in recent years, the frequency and performance of memory are required to be higher and higher. Just using DDR SDRAM (DDR), we can´t meet the demands. Compared with DDR, DDR2 SDRAM (DDR2) has higher speed, lower power, higher efficiency, and higher stability. A recent statistics shows that DDR2 will replace DDR in one or two years, but DDR is still prevailing today. For this reason, based on a common standard bus interface, an innovative design of the DDR/DDR2 SDRAM compatible controller is implemented and verified in this paper. If this compatible controller can be included in the computer architecture, the system will be more flexible and transplantable. Besides, during the period when DDR is replaced by DDR2, using this controller will greatly shorten time to market, lessen manual work and reduce product cost.