AT&T 3B2/300 Technical Reference Manual page 386

- - - - - - - - - - - - - - - - - - - - - - - - - - - FUNCTIONAL DESCRIPTION
DYNAMIC
RANDOM
ACCESS
MEMORY
CONTROLLER
ADDRESS BITS
_ (PPA23-16(1])
-
PRIWO
DATA BITS
IPDn7_nm1n
ADDRESS BITS
__JPPAIS-00[1])
-
STROBES
AND
ACKNOWLEDGE
SIGNALS
DIRECT MEMORY ACCESS SUBSYSTEM
,..----------,
1 JNTEGRAL
I CONTROLLERS
I
PAGE
I
REGISTERS
I
I
f
I
I
RESERVED
I
(Previously used
DMA
I
for the Integral
CHANNEL 0
I
Hard Disks.)
'
I
I
I
DMA
I
CHANNEL I
I
FD 1793-02
-
r
FLOPPY DISK
I
I
CONTROLLER
I
I
I
AMD 9517
DMA
I
DIRECT
CHANNEL 2
L
MEMORY
r
PORT A
ACCESS
I
CONTROLLER
I
I
I
DUAL
I
UNIVERSAL
I
ASYNCHRONOUS
I
RECEIVER/
I
TRANSMITTER
I
DMA
I
CHANNEL 3
I .
'
(
PORT B
I
I
I
I I
I
I
L----------.J
Figure 3-38: Direct Memory Access Subsystem - Functional Block Diagram
FLOPPY
DISK
DRIVE
'
- r
DATA
I
- I
SEPARATOR
RS-232C
PORT
- I
I
CONSOLE
I
RS-232C
PORT
r
CONTTY
I
- l
FUNCTIONAL DESCRIPTION 3-133