Patent ID: 7706309
Filing Date: 2010-04-27
Classification: H04L

Abstract:
1. A data transfer control method for controlling data transfer between a host and a target, the host includes a first data transfer control device, the target includes a second data transfer control device, the first and second data transfer control devices connected through a serial signal line, each of the first and second data transfer control devices including: a transmitter circuit that transmits data by current-driving the serial signal line using a half-duplex transfer method; a receiver circuit that receives data by detecting current flowing through the serial signal line using the half-duplex transfer method; and a transfer direction switch circuit that performs switching between a transmission direction and a reception direction, the transmission direction being a transfer direction in which data is transmitted by the transmitter circuit, and the reception direction being a transfer direction in which data is received by the receiver circuit; in the method: the transmitter circuit of the first data transfer control device transmitting the transfer direction switch request code through the serial signal line in addition to data transmitted through the serial signal line, the transmitter circuit of the first data transfer control device outputting an idle signal, logical level of which being continuously fixed at a first logical level in units of a given number of bits or more to the serial signal line after transmitting the transfer direction switch request code through the serial signal line, the transfer direction switch circuit of the first data transfer control device switching the transfer direction from the transmission direction to the reception direction when outputting the idle signal of a given number of bits, and the transfer direction switch circuit of the second data transfer control device switching the transfer direction from the reception direction to the transmission direction when the second data transfer control device has detected the idle signal of a given number of bits after detecting the transfer direction switch request code.