Lab1 Report
Class
Group
Members
Lab
Author
Date
Revision
Ayman El-Gamel
533576253.doc
16.552 Microprocessor II
4
Obi Atueyi (obi.atueyi@gmail.com)
Leonid Bafitos (leonidbafitos@hotmail.com)
Ayman El-Gamel (aelgamel@gmail.com)
1
Ayman El-Gamel
09/30/09
1.0
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References:
1. [TS03], The 8088 and 8086 Microprocessors, Tribel and Singh, Prentice Hall
2. [JC05], Designing Embedded Hardware, John Catsoulis, O’Reilly
Table of Contents
References: .......................................................................................................................... 2
Table of Contents ................................................................................................................ 2
Table of Figures .................................................................................................................. 2
2. Q & A .............................................................................................................................. 3
3. Modules Design .............................................................................................................. 3
3.2 Reset Circuit.............................................................................................................. 3
3.2 Clock Circuit ............................................................................................................. 6
2.3 Power Supply ............................................................................................................ 7
2.4 Power Filtering.......................................................................................................... 7
3. Appendices ..................................................................................................................... 8
3.1 Appendix A: Task List .............................................................................................. 8
3.2 Appendix B: Color Codes ......................................................................................... 8
3.3 Appendix C: Additional Images ............................................................................... 9
Table of Figures
Figure 1: Reset Fall-Time ................................................................................................... 4
Figure 2: Reset Rise-Time .................................................................................................. 5
Figure 3: Oscillator Out ...................................................................................................... 6
Figure 4: Clock out ............................................................................................................. 7
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2. Q & A
1. What is the signal to reset the 8284 clock generator? What is the pin number? Is
it active high or active-low?
Pin 10, Active-high
2. Which output pin of 8284 is to be used as clock signal to 8088 microprocessor?
What is the frequency of the clock?
Pin 8, 5.002 MHz
3. What is the purpose of decoupling capacitors?
The capacitors decouple the noise from the power supply. In this way, the noise is
removed and the chips have a constant and clean voltage source. The decoupling
capacitors should be placed as close a possible to the power pins of the devices.
3. Modules Design
3.2 Reset Circuit
The diode, D1, is for short circuit protection. The RC circuits in the RESET input were
based on the RESET time requirements of the 8088. While the RESET input to the
8284A is active-low, its output to the 8088 is active-high. The Reset and Initialization
section of the 8088 calls for a 50us low-to-high transition. Therefore, the high-to-low
transition on the input to 8284A is designed to exceed this (RC = 10K * 4.7uF = 50ms).
The low-to-high transition was simply selected to avoid aggressively discharging the
capacitor when the RESET button is depressed.
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Figure 1: Reset Fall-Time
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Figure 2: Reset Rise-Time
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3.2 Clock Circuit
The termination on the clock input was obtained from the Oscillator section of the 8284A
datasheet.
Figure 3: Oscillator Out
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Figure 4: Clock out
2.3 Power Supply
The regulator was selected because it sources up to 3A of current under ideal conditions.
Since the final design may demand more than 1A (and the physical nature of the board is
not ideal), an extra power supply circuit was introduced for future labs.
The rectifier, D3, is a shottky diode that prevents the circuit from being damaged if the
power supply polarities are reversed. The power supply decoupling circuit was obtained
from the Stability Consideration section of the datasheet. The 1A fuse is for short-circuit
protection.
2.4 Power Filtering
The ICs are decoupled with 0.1uF caps to shunt any voltage spikes attributed to logic
switching in the ICs.
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3. Appendices
3.1 Appendix A: Task List
Team Members
Obi
Ayman
Leo
Task
Draw schematic
Perform layout analysis
Design power supply
circuit
Build power supply circuit
Member
Obi
Obi
Obi
Obi
Ayman
Leo
Ayman
Leo
Obi
Obi
Leo
Ayman
Obi
Ayman
Leo
Obi
Leo
Ayman
Obi
Ayman
Leo
Test power supply circuit
Design reset circuit
Build reset circuit
Test reset circuit
Design clock circuit
Build clock circuit
Test clock circuit
Total time spent on the lab including the initial set-up and writing the report is 33 hour.
3.2 Appendix B: Color Codes
Signal
Type
+5VA
+5VB
Ground
Clock
Data
Control
Address
Layer
Number
Ayman El-Gamel
2
30
13
10
16
28
29
Wire
Color
Red
Orange
Black
Green
Blue
Yellow
Purple
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3.3 Appendix C: Additional Images
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