| 摘要 |
<P>PROBLEM TO BE SOLVED: To perform the efficient and fast processing of the whole copying machine without increasing a control load on a CPU even if mechano-electric components are controlled when the copying machine is controlled by the single CPU. <P>SOLUTION: An input/output port controller with which the printer or copying machine is equipped is provided with a write buffer 133 and a read buffer 134 between a CPU 131 and a shift register 135. Once the CPU 131 writes output signal data to the write buffer 133, a control register sequencer 150 loads the data to the shift register 135 and then serially transfers them to an output port 111 of an I/O control part 110. Then an input signal is held at an input prot 113 of the I/O control part 110, and serial data transfer from the input port 113 to the shift register 135 is carried out. These input signal data are written to the read buffer 134 and captured by generating an interrupt to the CPU 131. <P>COPYRIGHT: (C)2004,JPO |
