1. Overview & Purpose:

️· Device Type: A Video Palette RAM and Display Controller. It acts as a bridge between a microprocessor (MPU) and a video display.
️· Core Function: Manages color palette lookup and display memory access for video systems. Allows for dynamic color changes in video output.
️· Target Applications: Used in older graphics systems, video games, and applications requiring color palette manipulation.

2. Key Features:

️· Dynamic Color Palette: Allows for changing the colors displayed on a video screen in real-time.
️· MPU Interface: Communicates with a microprocessor for control and data transfer.
️· Address Sense Amplifiers: Increase video signal drive capability.
️· Programmable FIFO: Allows buffering of data to reduce CPU overhead.
️· Reset Functionality: Asynchronous reset to initialize the device and clear memory.
️· Configurable Modes: Supports various operating modes for different video formats.

3. Pin Descriptions & Functions:

️· VDD: Positive Supply Voltage (+5.0V).
️· VSS: Ground.
️· CEB1/CEB2: Chip Enable Inputs (active low). Used for MPU cycles.
️· R/WB: Read/Write Control. Determines whether a cycle is a read or write.
️· CONFIGSEL0-2: Configuration Select Inputs. Used to select RAM or register operations.
️· CONFIGBUS0-7: Data I/O Pins. Bidirectional data paths for MPU communication.
️· PIPE.IN0-3: Pipe inputs - inputs for data that will be stored in the FIFO.
️· PIPE.OUT0-3: Pipe outputs - outputs from data stored in the FIFO.
️· AFB: FIFO Almost Full output - Active low signal indicating FIFO is near capacity.
️· FFB: FIFO Full Output - Active low signal indicating FIFO is full.
️· RSB: Reset Input - Asynchronous reset to initialize the device.
️· BD.REV(0-3): Board Revision Input - Allows reading of the board revision data.
️· CLOCK.IN: Clock input signal - used for timing functions.

4. Key Electrical Characteristics & Timings

️· Supply Voltage (VDD): 4.75V to 5.25V.
️· Operating Temperature: -10°C to +85°C.
️· Maximum Power Dissipation: TBD (To Be Determined).
️· Input High Voltage (VIH): 2.2V to VDD + 0.3V.
️· Input Low Voltage (VIL): -0.5V to +0.8V.
️· Timing Parameters:
- CEB Cycle Time: 80ns.
- CEB Pulse Width: 65ns.
- Setup/Hold times for configuration and data: important for reliable communication with the MPU.
- Data access time (CONFIGBUS): 65ns.

5. Important Considerations

️· Tri-State Capability: The CONFIGBUS lines go into a high-impedance (tri-state) state during certain conditions (CEB high), allowing other devices to share the data bus.
️· FIFO Management: Proper management of the FIFO (using AFB and FFB) is crucial for optimizing CPU performance and avoiding data bottlenecks.
️· Reset Sequence: Using the reset line is essential for initializing the device and ensuring proper operation.



In essence, the MS622424 is a specialized IC that facilitates dynamic color manipulation and efficient data transfer in video systems. Understanding its pin functions, timing characteristics, and FIFO management is key to effectively incorporating it into a video application.