The MC68B45P is a CRT Controller (CRTC) designed by Freescale Semiconductor (NXP) and part of the Motorola 6800 family. This device generates the timing signals required to display characters and graphics on a cathode ray tube (CRT) monitor. The 'B' designates that this part operates at 2MHz.

Applications

• CRT Monitors: Core component in controlling the display on CRT monitors.
• Video Terminals: Used in video terminals for character and graphics generation.
• Graphics Cards: Implemented in early graphics cards to manage the display output.
• Embedded Systems with Displays: Integrated into embedded systems requiring visual output on a CRT screen.
• Arcade Games: Found in early arcade game systems for controlling the game's display.

Features

• Programmable Timing: Allows for flexible configuration of horizontal and vertical timing parameters.
• Character and Graphics Generation: Supports the generation of both character and graphics displays.
• Cursor Control: Provides control signals for displaying and manipulating a cursor on the screen.
• Light Pen Support: Includes support for light pen input.
• Interlace and Non-Interlace Modes: Supports both interlaced and non-interlaced display modes.

Benefits

• Flexible Display Control: Programmable timing parameters enable fine-grained control over the display.
• Simplified CRT Interface: Handles the complex timing requirements of CRT displays.
• Reduced System Complexity: Integrates CRT control functionality into a single chip.
• Enhanced Graphics Capabilities: Supports both character and graphics generation.
• Interactive Input Support: Light pen support allows for interactive input from the user.

The MC68B45P generates horizontal and vertical sync signals, as well as dot clock and display enable signals. It also provides signals for controlling the cursor and reading input from a light pen. The device is programmed through a set of registers that control the timing parameters, display format, and cursor attributes. It is typically packaged in a DIP (Dual In-line Package) and requires a single 5V power supply for operation. The 6845 is a versatile chip, and its design was influential, serving as the basis for the IBM CGA video adapter's controller. Its programmable nature allowed for a wide range of resolutions and display formats, making it suitable for diverse applications.