D8257C-5 200ns 8-bit Programmable DMA Controller IC 5V 120mA DIP-40

D8257C-5 200ns 8-bit Programmable DMA Controller IC 5V 120mA DIP-40

The µPD8257 is a programmable four-channel direct memory access controller designed to transfer data between peripheral devices and memory without heavy CPU involvement. It is built for 8080A/8085A-based systems and can move data efficiently by taking control of the bus when a peripheral requests service. This makes it useful where fast block transfers and reduced processor overhead are important.

When a DMA request arrives, the controller generates the proper memory address sequence, selects the correct channel, and handles the data transfer timing automatically. It supports both input and output data movement, so it can read from memory to a peripheral or write from a peripheral into memory. The device also provides control signals that keep the transfer synchronized with the system.

The µPD8257 also supports DMA read, DMA write, and DMA verify operations, along with terminal count and priority handling for multiple channels. Its role is to simplify data movement in microprocessor systems by managing repetitive transfer tasks in hardware, allowing the CPU to continue other work while the controller handles the transfer cycle.

Features:

• Four-channel DMA controller.
• Priority request logic.
• Channel inhibit logic.
• Terminal count and modulo 128 outputs.
• Automatic read mode.
• Single TTL clock.
• Single +5 V power supply operation.
• Expandable design for larger systems.
• Extended temperature range availability.

Specifications:

Pin Configurations:

Applications:

• 8080A/8085A microprocessor systems.
• Memory-to-peripheral data transfer.
• Peripheral-to-memory data transfer.
• Block data transfer control.
• DMA read operation.
• DMA write operation.
• DMA verify operation.

Package Contents:

• 1x D8257C-5 200ns 8-bit Programmable DMA Controller IC 5V 120mA DIP-40

Datasheet