An access control unit and method is proposed for use with an SDRAM
(Synchronous Dynamic Random-Access Memory) device to control each round
of burst-transfer type of access operation on the SDRAM device. The
proposed access control unit and method is characterized by that the
column-address strobe signal involved in each round of the burst-transfer
access operation is continuously set at active state for a period of
clock pulses equal in number to the specified burst length of the
burst-transfer access operation, rather than just for a period of one
pulse. This feature allows external circuitry to arbitrarily change the
burst length, and also allows no use of burst-stop command or a
precharge-interrupt method to stop each round of the burst-transfer
access operation, allowing the access control logic circuit architecture
to be more simplified than the prior art.
