| 摘要 |
PROBLEM TO BE SOLVED: To enable a host controller to be available for various data rates depending on input and output system of a memory card by suppressing an increase of mounting space and power consumption.SOLUTION: A host controller includes a card slot 9 equipped with the memory card, a transmission circuit 40 that encodes transmission data in a serial transfer format, a reception circuit 50 that decodes received data in the serial transfer format, a variable frequency clock generator 10 that generates a card clock and a transfer clock, a card clock output part 20 that outputs the card clock to the memory card, an interface part 60 that includes a transmission interface that serially transfers the transmission data from the transmission circuit to the memory card in synchronization with the transfer clock, and a reception interface that serially transfers the received data from the memory card to the reception circuit in synchronization with the transfer clock, and a setting register circuit 30 that holds setting information concerning an input/output method of the memory card, and controls a frequency of the transfer clock generated by the variable frequency clock generator 10 based on the setting information. |
