| 摘要 |
Disclosed is a controller and method for regulating a power-down mode in a memory card system. The memory card controller includes a central processor unit, a direct memory accessing (DMA) unit, a buffer, and a power-down detector. The central processor unit accepts commands from a host and the DMA unit stores the number of blocks requested by the host in response to instructions of the central processor unit. The buffer stores data that are read from an external storage device through the DMA unit. The power-down detector outputs a control signal to regulate a system clock by means of detecting a storage condition of the buffer and a read-out condition of the host. As the power-down mode begins, if the host does not read data stored in the buffer even when the buffer is full with data, it is possible to reduce power consumption by the memory card controller. |
