DDR1 Synchronous DRAM Alliance Memory DDR1 Synchronous DRAM is a high-speed CMOS double data rate synchronous DRAM. It is internally configured with a synchronous interface (all signals are registered on the positive edge of the clock signal, CK). Data outputs occur at both rising edges of CK and CK. Read and write accesses to the SDRAM are burst oriented. The Accesses start at a selected location and continue for a programmed number of locations in a programmed sequence. Accesses begin with the registration of a BankActivate command which is then followed by a Read or Write command.