| 摘要 |
PURPOSE:To prevent a signal collision due to the delay of a answer of a microcomputer by changing input/output directions of signals DAV and EOI off PIO in the process of switching from a source handshake to an acceptor handshake. CONSTITUTION:The microcomputer 2 decodes the three-wire handshake signal and bus control signal of an interface bus and performs processing for them. The microcomputer 2 accesses an input/output port of PIO1 to judge internal communication information on the standard digital interface or transmit and receive data. An input to and an output from an input/output port B of PIO1 are determined on bit basis. Input/output directions of signals DAV and EOI of PIO1 are changed in the process of switching from the source handshake to the acceptor handshake. |
