The IBM CGA (Color Graphics Adapter) was introduced by IBM in 1981 as an early graphics display adapter for the IBM PC and compatible systems. Here are some key features of the IBM CGA graphics card:

1. Release Time: IBM CGA made its debut in 1981, serving as one of the standard graphics adapters for the IBM PC. Its introduction marked a transition from the initial text-only mode to supporting graphical displays.

2. Resolution: The graphics resolution of IBM CGA was relatively low, with a maximum of 320x200 pixels. It also supported text modes, with a maximum resolution of 80 columns by 25 rows.

3. Color Capability: One of the notable features of IBM CGA was its color capability. It could display 16 colors, although in graphics mode, it typically only displayed 4 colors at a time (one foreground color and three background colors), determined by a fixed color palette.

4. Connector Interface: IBM CGA used a DB-9 connector for transferring graphics and text data as well as color information. Additionally, it included an adapter card that connected to the internal bus of the IBM PC.

5. Application: IBM CGA found widespread use in early personal computers, providing users with more visually appealing graphics and color displays compared to monochrome text mode. However, due to its limited resolution and color capabilities, it was eventually replaced by more advanced graphics adapters.

IBM(CGA)Technical_Reference:

IBM Color Graphics Adapter (CGA).pdf

ISA-CGA Schematic Diagram:

ISA-CGA6845-1.5.pdf

CPLD_A(U4)_Schematic Diagram:

ISA-CGA6845-CPLD_A-1.5.pdf

CPLD_B(U5)_Schematic Diagram:

ISA-CGA6845-CPLD_B-1.5.pdf