VL82C37A Datasheet | VLSI

FEATURES - Low-power CMOS version of popular 8237A DMA controller - Four DMA channels - Individual enable/disable control of DMA requests - Directly expandable to any number of channels - Independent auto-initialize feature for all channels - High performance 8 MHz version available - Transfers may be terminated by endof-process input - Software controlled DMA requests - Independent polarity control for DREO and DACK signals DESCRIPTION The VL82C37A Direct Memory Access (DMA) Controller serves as a peripheral interface circuit for microprocessor systems, and is designed to improve system performance by allowing external devices to directly transfer information from the system memory. Memory-to-memory transfer capabil~y is also provided. The VL82C37A DMA Controller offers many programmable control features that enhance data throughput and system performance. Dynamic reconfiguration is permitted under program control. The VL82C37A is designed to be used with an external 8-bit address register such as the 8282. In addition to the four independent channels, the VL82C37A is expandable to any number of channels by cascading additional controller devices. Three basic transfer modes allow the user to program the types of DMA service. Each channel can be individually programmed to auto-initialize to its original condition following an end-ofprocess (EOP) input. Each channel also has a 64K address and word count handling ability. The VL82C37A DMA Controller is available in S MHz and 8 MHz clock frequencies. PIN DIAGRAM BLOCK DIAGRAM -l OR -l OW -MEMR -MEMW VCC READY Hl DA ADSTB AEN HRO -CS Cl K RESET DACK2 DACK3 DRE03 DRE02 DRE01 DREOO GND A7 A6 AS A4 -EOP A3 A2 A1 AO VCC DBO DB1 DB2 DB3 DB4 DACKO DACK1 DB5 DB6 DB7 ORDER INFORMATION Part Number VL82C37 A-OSPC Vl82C37A-OSCC VL82C37 A-OSQC Vl82C37 A-08PC Vl82C37 A-08CC Vl82C37A-OSOC Clock Frequency S MHz 8 MHz Package Plastic DIP Ceramic DIP Plastic Leaded Chip Carrier (Pl CC) Plastic DIP Ceramic DIP Plastic...