MP-LA Parallel Interface

The MP-LA Parallel Interface is a 5 1/4 inch x 3 1/2 inch board implemented with the 6820 peripheral interface adapter integrated circuit which is used to interface a parallel data device to the computer. The board is provided with two separate connections along the edge of the board. Each connector contains eight data lines which may be programmed for either outputs or inputs, one "data ready" line, and one "data accepted" line for full handshake control. All data lines are fully buffered with bi-directional transceivers to allow eight inputs and eight outputs, 16 inputs and no outputs or 16 outputs and no inputs. Programming of a particular set of data lines is done via jumpers on the MP-L board. Software control of interrupt lines and the polarity of the handshake lines is provided.

Motorola replaced MC6820 chip with MC6821. There was only minor changes in the electrical characteristic, both chips were functional identical.

Introduced by Southwest Technical Products Corporation in 1976. The MP-LA kit cost $35

Board Photo (49K JPG)

Board Photo High Resolution (160K JPG)

Assembly Instructions (113K PDF)

Schematic (200K PDF)

Michael Holley's SWTPC Collection Home Page