AT&T 3B2/300 Technical Reference Manual page 332

- - - - - - - - - - - - - - - - - - - - - - - - - - FUNCTIONAL DESCRIPTION
DUAL
PORT
DYNAMIC
RANDOM
ACCESS
MEMORY
CONTROLLER
DATA
BITS 07-00
(PD07-00[1])
-
-
ADDRESS
BITS 15-00
(PPAIS-00[1])
- -
-
STROBES
AND
ACKNOWLEDGE
SIGNALS
DIRECT MEMORY ACCESS SUBSYSTEM
r------------,
I
INTEGRAL
I
CONTROLLERS
I
I
I
I
I
DMA I
CHANNEL 0 I
NEC 7261
HARD DISK
CONTROLLER
DMA
AMO 9517
CHANNEL 1
WO 2797-02
-
DIRECT
I
FLOPPY DISK
I
MEMORY CONTROLLER
ACCESS
CONTROLLER
DMA
CHANNEL2
- -
PORT A
DUAL
UNIVERSAL
ASYNCHRONOUS
RECEIVER/
TRANSMITTER
DMA
CHANNEL 3
I -
.
I
I -
PORT B
I
I I
I I
I I
I I
L------------.J
Figure 3-26: Direct Memory Access Subsystem - Functional Block Diagram
HARD
DISK
DRIVE
O
HARD
~
DISK
DRIVE 1
FLOPPY
DISK
DRIVE
RS-232C
PORT
I
I
CONSOLE
RS-232C
PORT
. I
I
CONTTY
FUNCTIONAL DESCRIPTION 3-79