IBM Options and Adapters - IBM Monochrome Display and Printer Adapter
The IBM Monochrome Display and Printer Adapter is a section of IBM's Technical Reference: Options and Adapters in the Personal Computer Hardware Reference Library, part number 6361511. It is IBM's technical reference for the card usually called the MDA. The scan is 32 pages.
Contents
[edit | edit source]Page numbers are the section's own.
- Monochrome display adapter function (pp. 1-10). A Motorola 6845 CRT controller and 4 KB of display RAM with no parity, which the processor can access directly. Two bytes are fetched from the buffer in 553 ns, a data rate of 1.8 MB/s. An 8 KB character generator holds 256 characters, each 7 by 9 PELs in a 9 by 14 box. The adapter needs an 18 kHz monitor and does not support a light pen with a P39-phosphor display. The programming section covers the 6845 registers, the CRT control port at hex 3B8 and the status port at hex 3BA. The 9-pin display connector has ground on pins 1 and 2, +Intensity on 6, +Video on 7, +Horizontal on 8 and −Vertical on 9, with signals at 0.0 to 0.6 V dc down and +2.4 to 3.5 V dc up.
- Printer adapter function (pp. 11-18): 12 latched TTL output points and 5 steady-state input points, the register map and the 25-pin D-shell connector.
- Logic diagrams (from p. 19), covering both functions.
What this document does not contain
[edit | edit source]It is a design reference. There is no parts list and no fault-finding procedure.
Download: IBM Options and Adapters - IBM Monochrome Display and Printer Adapter.pdf