![](http://datasheet.mmic.net.cn/260000/AM8530_datasheet_15869217/AM8530_175.png)
SCC Application Notes
AMD
7–26
PA16R4
PAL DESIGN SPEC
PAT 002
JOE BRICH 9 SEPT 83
68000 TO 8500 OR 9500 PERIPHERALS
ADVANCED MICRO DEVICES
CLOCK /CS RW /LDS /WO /AS FCO FC1 FC2 GND
/OE /INTA /ACK /C /B /A /DLDS /RD /WR VCC
A := A*/B + B *C + /AS
B := A*/C + /A*C + /AS
C := /A*/B*AS + B*C*AS
DLDS := LDS
RD = LDS*DLDS*RW*/INTA + /INTA*/A*/B*C*WO + INTA*/B*A + ACK * LDS
DESCRIPTION
THIS PAL DEVICE INTERFACESN 85XX TYPE PERIPHERALS TO THE 68000
MICRO PROCESSOR. IT INSERTS 1 OR 2 WAIT STATES AS SELECTED BY
/WO = 0 IS ONE AND /WO = 1 IS TWO WAIT STATES. FOUR WAIT STATES
ARE INSERTED DURING THE INTERRUPT ACKNOWLEDGE CYCLES. ALSO THE
RD OUTPUT GENERATED DURING INTA IS A FUNCTION OF THE INTERNAL
STATE MACHINE AND NOT A FUNCTION OF LDS. OE CAN BE LEFT OPEN
SINCE THE FLIP–FLOP OUTPUTS ARE NOT USED DIRECTLY. THE FALLING
EDGE OF RD IS DELAYED IN ORDER TO GUARANTEE THE CS TO RD SETUP
TIME REQUIREMENTS.
Figure 7–16. PAL Equations
7.6
7.6.1
The changing data-processing environment has created attractive opportunities for dis-
tributed processing, encouraging both users and vendors to support the concept. Distrib-
uted processing provides either functional or geographical dispersion while integrating the
dispersed parts into a coherent system.
Am7960 AND Am8530H APPLICAT ION
Distributed Data Proc essing Overview
The main advantages of distributed processing power are:
a. Efficiency—
Specialized machines perform their functions in an efficient manner. Large,
centralized systems are often multi-tasked and they do not necessarily perform all the
functions with equal efficiency.
b. Low Cost—
i.
A less complex computer, or other forms of distributed intelligence, is required.
ii. It simplifies certain applications where only data accessing is required.
c. Control—
Users have control of most of the computing power in the system organization.
d. Unlimited Access—
Distributed processing power allows the user greater access to the machine operating
system and hardware. In large, centralized systems, very few users are allowed to
access the mainframe’s operating system and hence cannot take full advantage of all
the computer’s power.
e. Response Time—
Local processing eliminates the relatively slow common-carrier lines in favor of high-
speed channels. Distributed processing can improve response time for certain
applications that can be partitioned for simultaneous execution in parallel on multiple,