Adapter Card for Host-Printer Interfaces
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-28
A single, more efficient adapter circuit card can be used between the interfaces of a host processor system and attached printer by allowing the direct memory access (DMA)controllers of both the host and printer to write into or read from random-access memory on the adapter and downloading microcode from the printer to the adapter each time the printer is powered. Referring to the schematic of the adapter card in the figure, the card is connected to the host interface through Link-TC module 1 and to the printer interface, identified as Task, via data and address buses 2, 3 and 4, and initial microcode (IML) and Task control lines 5, through respective registers 6. The host uses a serial, bidirectional, asynchronous communication system and initiates all communications.