Patent ID: 7689763

Claim:
A method of operating an interface for reducing pin count in an integrated circuit (IC) when interfacing with a synchronous dynamic random access memory chip (SDRAM), the SDRAM having a plurality of input address pins, a plurality of input/output data pins, and an internal memory, the IC having a set of data pins, comprising: connecting together each one of the plurality of input/output data pins of the SDRAM to a respective one of the plurality of input address pins of the SDRAM to form a shared bus; interfacing the IC to the SDRAM through the shared bus, wherein each line of the shared bus is connected to a respective one of the set of data pins of the IC, a respective one of the plurality of input address pins of the SDRAM, and a respective one of the plurality of input/output data pins of the SDRAM; during a first clock cycle, sending a write command from the IC to the SDRAM via command lines to initiate a write operation at the SDRAM, sending an address for writing data via the shared bus from the set of data pins of the IC to the plurality of input address pins and the plurality of input/output data pins of the SDRAM, and asserting mask signals on mask lines by the IC such that the SDRAM does not write the address sent to the plurality of input/output data pins of the SDRAM as data for the write operation into the internal memory of the SDRAM; during a second through M clock cycles, sending write data via the shared bus to the plurality of input address pins of the SDRAM and the plurality of input/output data pins of the SDRAM, and deasserting at least one of the mask signals on the mask lines by the IC, wherein the SDRAM writes the write data into the internal memory of the SDRAM; and during an M+1 clock cycle, sending an activate command from the IC to the SDRAM along the command lines, sending a bank address via the shared bus from the set of data pins of the IC to the plurality of input address pins of the SDRAM and the plurality of input/output data pins of the SDRAM, and asserting the mask signals on the mask lines.