• Compatible With: Intel 8237A DMA Controller
• Device Type: Programmable DMA Controller
• Technology: CMOS
• Package Type: 40-Pin DIP

General Features

• Fully compatible with Intel 8237A architecture
• Four independent DMA channels
• High-speed memory-to-peripheral data transfers
• Reduces CPU overhead during data movement
• CMOS low-power operation
• Priority arbitration between channels

DMA Channels

• Number of DMA Channels: 4
• Independent address and count registers for each channel
• Programmable transfer modes
• Automatic address increment/decrement

Transfer Modes

• Single Transfer Mode
• Block Transfer Mode
• Demand Transfer Mode
• Cascade Mode

Addressing

• Address Width: 16 bits
• Direct access to 64 KB memory space
• Separate current and base address registers

Data Bus Interface

• Data Bus Width: 8 bits
• Bidirectional data bus
• Compatible with:
  • 8085 systems
  • 8086/8088 systems
  • Z80 systems
  • Other microprocessor-based designs

Timing Characteristics

• High-speed DMA operation
• Typical clock frequency:
  • Up to 5 MHz (standard versions)
  • Higher for selected speed grades

Electrical Characteristics

• Supply Voltage:
  • 4.5 V to 5.5 V
  • Nominal: 5 V
• CMOS low-power design
• TTL-compatible inputs and outputs

Control Signals

• DREQ0–DREQ3 (DMA Request Inputs)
• DACK0–DACK3 (DMA Acknowledge Outputs)
• HRQ (Hold Request)
• HLDA (Hold Acknowledge)
• MEMR / MEMW
• IOR / IOW
• EOP (End of Process)

Priority Modes

• Fixed Priority
• Rotating Priority

Auto Initialization

• Automatic reload of:
  • Address registers
  • Word count registers
• Useful for repetitive DMA operations

Package

• Package Type: PDIP
• Pin Count: 40 Pins
• Mounting Style: Through-Hole

Operating Temperature

• Commercial Version:
  • 0°C to +70°C

Key Features

• Four DMA channels
• Intel 8237A compatible
• CMOS low-power operation
• Multiple transfer modes
• Auto-initialize capability
• Programmable priority schemes
• Reduced CPU workload
• 40-pin DIP package

Typical Applications

• Personal computers
• Industrial controllers
• Data acquisition systems
• Communication equipment
• Floppy disk controllers
• Embedded systems
• Instrumentation equipment
• Microprocessor development systems