Presentation based on PCB Designing and 8051 Microcontrollers..

1. Printed Circuit Board(PCB’S)
1
http://saturnpcb.com/pcb_services.htm

2. Overview
What is a PCB?
Why use a PCB?
How do I make a PCB?
2

3. Printed Circuit Board

Circuit connects components through board

Made of alternating layers of conducting and
insulating materials
3
http://www.seilpcb.co.kr/products/images/2_1_img5.gif

4. Why PCB?
• Features
• Surprisingly Affordable
• Highly reliable
• Compact
• Drawbacks
• Requires more layout than other board types
• Higher initial cost than wire wrap or point-to-point
construction
4
http://en.wikipedia.org/wiki/File:Breadboard_complex.jpg

5. PCB Design Steps
1 Design the circuit
2 Place the components
3 Route the wires
4 Manufacture
5

6. EDA Software
• PCB design software package
• Design the circuit (Schematics editor)
• Place the components (PCB editor)
• Route the wires (Autorouter module)
• Examples:
• Express Schematics
• ExpressPCB
• Proteus(ISIS)
6

7. Schematic Capture

Pin in/outs

Components

Interconnections

Easily Readable

High-Level Block
Diagram
7
All pictures of schematics and EAGLE screenshots from http://www.sparkfun.com/tutorials/108
and http://www.sparkfun.com/tutorials/109

8. Placement of Components
• Rat’s Nest
8

9. Placement of Components
• Place big components first- e.g. microcontroller
• Place components in separate functional groups
• Put a ground plane under all components
9

10. Signal Routing Component
Placement
Surface mount
• Top and bottom planes
• Minimal routing area
Through-hole mounted
• All components on same side
• Reduces routing area on all planes
10http://www.ehow.com/how_8306661_solder-mini-components.html
http://blog.amal.net/?p=188

11. Signal Routing
Traces are wires connecting components
Traces can be routed through multiple layers
11

12. Vias and Pads
Vias are connections between layers
Pads are copper areas for pin connections
12

13. Viewplot Check
13

14. Cost Estimate
14
•www.pcbfabexpress.com

15. THE 8051 MICROCONTROLLER
PIN DIAGRAM
IT’S COMPONENTS
IT’S ADVANTAGES
DISADVANTAGES
COMPARISON WITH DIFFERENT MEMBERS
15

16. 8051 Basic Component
4K bytes internal ROM
128 bytes internal RAM
Four 8-bit I/O ports (P0 - P3).
Two 16-bit timers/counters
One serial interface
64k external memory for code
64k external memory for data
210 bit addressable
Microcontroller

17. 8051
Foot Print
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
RST
(RXD)P3.0
(TXD)P3.1
(T0)P3.4
(T1)P3.5
XTAL2
XTAL1
GND
(INT0)P3.2
(INT1)P3.3
(RD)P3.7
(WR)P3.6
Vcc
P0.0(AD
0)P0.1(AD1)
P0.2(AD
2)P0.3(AD3)
P0.4(AD4)
P0.5(AD5)
P0.6(AD6)
P0.7(AD7)
EA/VPP
ALE/PROG
PSEN
P2.7(A15)
P2.6(A14
)P2.5(A13
)P2.4(A12
)P2.3(A11
)P2.2(A10)
P2.1(A9)
P2.0(A8)
8051
(8031)
(8751)
(8951)

18. IMPORTANT PINS (IO Ports)IMPORTANT PINS (IO Ports)
 Port 2Port 2
（（ pins 21-28pins 21-28 （（ P2.0P2.0 ～～
P2.7P2.7 ））
8-bit R/W - General8-bit R/W - General
Purpose I/OPurpose I/O
OrOr highhigh byte of thebyte of the
addressaddress bus forbus for
external memoryexternal memory
designdesign

19. IMPORTANT PINS (IO Ports)IMPORTANT PINS (IO Ports)
 Port 3Port 3
（（ pins 10-17pins 10-17 （（ P3.0P3.0 ～～
P3.7P3.7 ））
 General Purpose I/OGeneral Purpose I/O
 if not using any of theif not using any of the
internal peripheralsinternal peripherals
(timers) or external(timers) or external
interrupts.interrupts.

20. Register
sA
B
R0
R1
R3
R4
R2
R5
R7
R6
DPH DPL
PC
DPTR
PC
Some 8051 16-bit Register
Some 8-bitt Registers of
the 8051

21. Data memory
XM
DM
MOV A,62H
MOV R1,#62H
MOV A@R1
MOV A,0A2H
MOV R1,#0A2H
MOV A@R1

22. Comparison some of the 8051 Family Members
ROM RAM Timer
8051 4k 128 2
8031 - 128 2
8751 4k eprom 128 2
8052 8krom 256 3
8032 - 256 3
8752 8k eprom 256 3

23. Comparison of the 8051 Family Members
ROM type
 8031 no ROM
 80xx mask ROM
 87xx EPROM
 89xx Flash EEPROM
89xx
 8951
 8952
 8953
 8955
 898252
 891051
 892051
Example (AT89C51,AT89LV51)
 AT= ATMEL(Manufacture)
 C = CMOS technology
 LV= Low Power(3.0v)

24. Advantages of Microcontroller
based System
As the peripherals are integrated into a single chip, the overall system
cost is very less
The product is of small size compared to micro processor based
system
The system design now requires very little efforts
As the peripherals are integrated with a microprocessor the system is
more reliable
Though microcontroller may have on chip ROM,RAM and I/O ports,
addition ROM, RAM I/O ports may be interfaced externally if required
On chip ROM provide a software security
SJCET

25. Disadvantages of microprocessor
The overall system cost is high
A large sized PCB is required for assembling
all the components
Overall product design requires more time
Physical size of the product is big
A discrete components are used, the system is
not reliable
SJCET