A general purpose high speed parappel data lnik (called PDL) between IBM main frame and a S-100 bus for micro-computers is designed and implemented.
This PDL enables many I/O devices to be easily interfaced to IBM through micro-computer. On the IBM side, 2701 PARALLEL DATA ADAPTER is utilized. On the micro-computer end, Direct Memory Access (DMA) technique is used. The data transfer scheme of IBM is serial-by-half-word (16-bit), parallel-by-bit and that of the micro-computer is serial-by-byte (8-bit), parallel-by-bit. Data adapter for 16 to 8 conversion and the reverse is designed to accommodate different data widths. Communication between IBM and micro-computer is interrupt-driven. IBM can disable interrupt with a command word to this Parallel Data Link.
PDL is applied in an on-going exprement for distributed graphics system involving graphic color monitor, graphic printer, digitizer, and the others. KOREAN character graphics for motion is aslo experimented on aid of additional software being developed.
