| 摘要 |
PROBLEM TO BE SOLVED: To provide a data transfer system which enables a host device to transmit data less than a free area smaller than an input byte width without stopping the transfer when the free area is available in a buffer of an FIFO and the host device tries to transfer data smaller than the free area. SOLUTION: The host device 2 transmits and receives data. A transmission FIFO 11 receives the transmit data 203 from the host device 2 and transmits the transmit data 108 to a slave device 3 through a selector 10. A receiving FIFO 12 transmits received data 107 received from the slave device 3 as received data 103 to the host device 2. A transmission FIFO free byte number detection circuit 13 detects the number of unused bytes in the transmission FIFO 11 with a remaining byte number display signal 106. A receiving FIFO effective byte number detection circuit 14 detects the number of unused bytes in the receiving FIFO 12 with a remaining byte number display signal 105. A DMA circuit 15 outputs a data transmission/reception request signal to the host device 2. COPYRIGHT: (C)2004,JPO
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