A8237 Datasheet, PDF (1/22 Pages) Altera Corporation – PROGRAMMABLE DMA CONTROLLER

®
April 1999, ver. 1.01
a8237
Programmable
DMA Controller
Data Sheet
Features
General
Description
s a8237 MegaCore function implementing a programmable direct
memory access (DMA) controller
s Optimized for FLEX^® architecture
s Provides four independent channels
s Offers static read/write or handshaking modes
s Includes direct bit set/reset capability
s Uses approximately 1,201 FLEX logic elements (LEs)
s Functionally based on the Intel 8237A and Harris 82C37A devices,
except as noted in “Variations & Clarifications” on page 24
The a8237 MegaCore function implements a programmable DMA
controller, which controls memory-to-peripheral and memory-to-
memory data transfers and provides block memory initialization
capability. Four independently programmable channels are available in
the a8237, and DMA requests can be made via hardware or software.
Figure 1 shows the symbol for the a8237.
Figure 1. a8237 Symbol
clk
hlda
ncs
neopin
niorin
niowin
ready
reset
ain[3..0]
dbin[7..0]
dreq[3..0]
A8237
adstb
aen
dben
dmaenable
hrq
neopout
niorout
niowout
nmemr
nmemw
aout[7..0]
dack[3..0]
dbout[7..0]
Altera Corporation
5
A-DS-A8237-01.01