Printed Circuit Board Sample Essay

1 ) Introduction

1. 1 ) Aim

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Assorted conventional symbols and diagrams are familiarized and a conventional is a aggregation of electronic symbols connected together with practical “wires” . When manufacturing a printed circuit board ( PCB ) . a conventional is needed to supply input ( a netlist ) to the layout and routing tool ( Varteresian. 2002 ) . In other words. the gaining control of a conventional diagram is a convention to PCB. subsequent building and testing. The design of PCBs is really widely used in electronic equipment and systems. for illustration. good EMC ( Electromagnetic Compatibility ) patterns. These PCB-level EMC patterns normally help accomplish the needed EMC public presentation at a much lower cost than alternate EMC steps at higher degrees of integrating. such as whole-product shielding. They besides improve signal unity in both parallel and digital circuits ( Armstrong. Aug 1999 ) . Power uncoupling techniques can better the power supply of a PCB and transmittal lines techniques are a portion of the PCB layout ( Armstrong. Oct 1999 ) . The MM232R is a illumination development faculty which uses FTDI’s FT232RQ. In this assignment. MM232R needed to be designed harmonizing to the datasheet.

Besides. switches of four pins besides needed to be designed. but merely two pins were used in diagram. PIC18F1320. a microcontroller. which features six enhanced power-managed “software controlled” manners. power ingestion every bit low as 0. 1 microamps in standby manner and a broad operating electromotive force scope from 2 to 5. 5 Vs which makes this device ideal for battery managed applications ( Unknown. 2007 ) . It has some advantages. such as viz. and high computational public presentation at an economical monetary value. with the add-on of high endurance Enhanced Flash plan memory.

There are a scope of characteristics that can significantly cut down power ingestion during operation. including Alternate Run Modes. Multiple Idle Modes. On-the-fly Mode Switching and Lower Consumption in Key Modules ( Unknown. 2004 ) . A pre-programmed PIC18F1320 was made available for proving intent. This assignment is a simple two LED show. 3 push button switches and USB interface PIC18F1320 based PCB. The Pickit connection enables this device to be programmed with the user maps required. The LEDs maintain flashing when the PCB was connected with the power supply or USB overseas telegram. Pushing the reset button ( W1 ) . both LEDs go out for a minute so both come on for a minute and so get down blinking once more. The purpose of this assignment is to do the flashing lessening ( addition ) in frequence by forcing and keeping down W2 ( W3 ) . This assignment consists of three parts: PCB design. PCB building and PCB testing.

1. 2 ) Background

PCB means printed circuit board. besides known as a printed wiring board. It is used in electronics to construct electronics devices. A PCB serves two intents in the building of an electronic device ; it is a topographic point to mount the constituents and it provides the agencies of electrical connexion between the constituents ( Unknown. 2003 ) . It is a thin board made of fibreglass or a similar stuff. Electrical wires are “printed” onto the board. linking the cardinal processor to other constituents on the board. Some illustrations of PCBs include motherboards. RAM french friess. and web interface cards. Sometimes PCBs are abbreviated as “PC boards” . which is suiting. since the boards are normally used in personal computing machines. However. PCBs are besides found in other types of electronic devices. such as wirelesss. telecastings. and computing machine proctors. Because PCBs are comparatively level. they can besides be used in thin devices such as laptops and portable music participants ( Unknown. 2012 ) .

1. 3 ) Block Diagram

The basic edifice blocks of a encouragement convertor circuit are shown in Fig 1. 1.

Figure 1. 1 Block Diagram
2)Requirements analysis

PCB Design: To get down with. MM232R and three switches of four pins are needed to plan in ARES. and so the MM232R is needed to pull in ISIS. Following packaging the MM232R and three switches in ISIS. After the circuit diagram is completed. it should be PCB layout. During the PCB layout. all connections should be near the border of the PCB for easy entree. The PCB will be powered from the MM232R USB interface but when the MM232R is non inserted power connexion can be made to J1 and J2 Veropins so do certain these two pins are far plenty apart to avoid shorting power connexions. There should be room at each of the four corners of the PCB for a no-good pes. which will necessitate a 5mm hole. The gum elastic pes itself is 13mm in diameter and must be allowed for on the PCB layout.

PCB Construction: First of all. all the holes in the PCB have to be drilled. Most of them are 0. 8mm but a few such as switches and veropins are 1. 0mm and rubber pess are 5. 0mm. There are six resistances ( R1=100R. R2=22k. R3=R4=470R. R5=R6=10k ) . one capacitance ( C1=100n ) and three pickit connections. Then soldering the PCB. the LEDs should stand 3mm off from the PCB surface. Following proving the PCB. look into that if it is shorted anyplace on the power rail. Besides check that the right pins on the PIC have 0V and +5V values and the MM232R connection has the right electromotive force power values. The followers shows the trial agenda:

a ) imitating the circuit diagram by utilizing the CRO ; B ) proving PCB without PIC or MM232R inserted ;
degree Celsius ) proving PCB after PIC was inserted and add the right power connexions ; vitamin D ) proving PCB after MM232R was besides inserted and stop uping in a USB overseas telegram to a PC/laptop. 3)Possible solutions

MM232R Design: Harmonizing to the MM232R datasheet. the MM232R can be designed in ARES and so box it so that it is can be found in ISIS.

Simulation in ISIS: Adding the MTIPickit. HEX to the PIC18F1320 and CRO which C connects D1 and D connects D2 in ISIS. so set the MM232R to be excluded from the simulation ( redact the belongingss for this device ) and the simulation diagram would demo by snaping the start/stop icon. Drilling: The 0. 8mm holes can be drilled in the land floor boring room and 1. 0mm and 5. 0mm holes can be drilled in the first floor boring room in Hawke. Testing: When the PCB had been completed constructed so performed a power on trial without PIC or MM232R inserted by linking +5V to the veropins. Check that the PCB was non shorted anyplace on the power rail. Looked at the PIC datasheet to find the right pins and look into that the pins have 0V and +5V values. Then insert the PIC in the right manner around but without the power connected. Add the right power connexions and the LEDs start blinking alternately. Following insert the MM232R and stop up the USB overseas telegram which connected with computing machine. the computing machine would acknowledge that a USB device has been inserted and burden. 4)Implementation

4. 1 ) PCB Design

First of all. the MM232R was designed harmonizing to its datasheet in ARES and so it was packaged so that it can be found in ISIS. Next three switches ( four pins ) were designed and packaged by utilizing the same methods. nevertheless. merely two pins were used in the circuit diagram. It needs to change over the conventional into a individual side PCB layout in ARES after the circuit diagram was completed. The PCB was required 2?2 inches in size and the tablets used for the DIL constituents were egg-shaped instead than the smaller circle that is the default in the ARES library in order to supply adequate Cu tablet when soldering. All connections were placed near the border of the PCB for easy entree. The LEDS stood 3mm off from the PCB surface. In add-on. J1 and J2 Veropins were placed far adequate apart to avoid shorting power connexions. Finally. rubber pess ( 5mm hole ) were required in the four corners of the PCB. the gum elastic pes itself is 13mm in diameter. The PIC Circuit Diagram sees Figure 4. 1.

Figure 4. 1 PIC Circuits Diagram

The designed PCB sees Figure 4. 2:

Figure 4. 2 Designed PCB
The 3D vision of the top and bottom beds sees Figure 4. 3:

( a ) top bed ( B ) underside layer Figure 4. 3 The 3D vision of 2-Phase PIC circuit board

4. 2 ) PCB Construction

The hardware paradigm was built on a PCB for dependability utilizing both the top and bottom beds. see Figure 4. 4.

( a ) top bed ( B ) underside layer Figure 4. 4 2-Phase PIC circuit board demoing its constituents

4. 3 ) PCB Testing

Inserted the PIC and used the power supply to supply the power ( J1 connects +5V and J2 connects 0V ) . Then connected the PIC to oscilloscope ( pin8 connects channel one and pin17 connects impart two ) . see Figure 4. 5.

Figure 4. 5 PIC connects with an CRO
Inserted the MM232R and made a USB overseas telegram stopper in to a computing machine. Since this PCB is designed to be powered from the USB connexion. it can non be connected with an external power supply. see Figure 4. 6. [ movie ]

Figure 4. 6 MM232R connects with a computing machine by utilizing a USB overseas telegram 5)Results

The undermentioned wave forms were obtained by imitating the PIC circuit diagram in ISIS. They show the reset. slow and fast severally. see Figure 5. 1.

a ) reset ( W1 )

B )

( B ) slow ( W2 )

( degree Celsius ) fast ( W3 )

Figure 5. 1 The wave forms of LEDs by imitating in ISIS

The undermentioned wave forms were got when the PIC connected an CRO. the top 1 is about the wave form of D1 with channel one and the bottom 1 is about the wave form of D2 with channel two. They show the reset. slow and fast severally. see Figure 5. 2.

a ) reset ( W1 )

B ) slow ( W2 )

( degree Celsius ) fast ( W3 )

Figure 5. 2 The wave forms of LEDs by utilizing an CRO

Insert the MM232R and a USB overseas telegram plugged in to a computing machine. and so detected the device and found out the COM port figure is 11. Following set to the right COM port figure 19200 Baud. with Flow control was set to none and a text message appeared on the PUTTY screen and the LEDs started blinking. After that pressed any key on the keyboard and the mark on message appeared once more. the LEDs continued blinking. The text messages on the PUTTY see Figure 5. 3.

Figure 5. 3 Text messages on the PUTTY
6)Discussion of consequences

The wave forms from the experiment and simulation are similar. but the simulation is more accurate than the experiment. this is because the experiment may bring forth some mistakes. including system mistake and human mistakes ( such as misreading. misreckoning and parallax ) . In add-on. the informations can be recorded straight no affair which data we want to read. In this experiment. we can cipher the frequence and Vp-p easy by the information has shown in the old chapter. When the frequence reached the lower limit in the simulation. f1=2. 759Hz. Vp-p1=4. 85V. f2=2. 797Hz and Vp-p2=4. 75V. but it merely shows the frequence is less than 20Hz in the experiment. However. when the frequence reached the upper limit in the simulation. f1=23. 3Hz. Vp-p1=4. 90V. f2=24. 4Hz and Vp-p2=4. 90V. it shows the frequence is 24. 8880Hz in the experiment. both of them are closed. It was supplied 5V power in the experiment and it is close to 5V in the simulation.


Having completed the assignment. the undermentioned decision can be deduced: the PIC is an easy to utilize device because of it has been programmed. but it needs to the MM232R is an easy to utilize device due to it can link with the computing machine straight. The experiment has demonstrated that the PCB can be supplied power by utilizing a power supply or the USB connexion. The consequences show that the wave forms from the experiment and simulation have some mistakes. such as the frequence and the electromotive force. but they are accepted. The gaining control of a conventional diagram. it is transition to a PCB and subsequent building and testing is a complex procedure necessitating a broad scope of different practical accomplishment. The Pickit connection enables the PIC18F1320 to be programmed with the user maps required.


Armstrong. M. K. . August. 1999. PCB design techniques for. ELECTRONICS & A ; COMMUNICATION ENGINEERING JOURNAL. pp. 185-194.

Armstrong. M. K. . October 1999. PCB design techniques for. ELECTRONICS & A ; COMMUNICATION ENGINEERING JOURNAL. pp. 218-226.

Unknown. 2003. What is a PCB. [ Online ]Available at: hypertext transfer protocol: //www. wisegeek. com/what-is-a-pcb. htm
[ Accessed 5 12 2012 ] .

Unknown. 2004. Microchip. [ Online ]Available at: hypertext transfer protocol: //nnp. ucsd. edu/phy120b/pic_manuals_pdf/pic18F_1320. pdf [ Accessed 3 12 2012 ] .

Unknown. 2007. Microchip. [ Online ]Available at: hypertext transfer protocol: //www. micro chip. com/wwwproducts/Devices. aspx? dDocName=en010265 [ Accessed 3 12 2012 ] .

Unknown. 2012. PCB. [ Online ]Available at: hypertext transfer protocol: //www. techterms. com/definition/pcb
[ Accessed 5 12 2012 ] .

Varteresian. J. . 2002. Manufacturing Printed Circuit Boards. United States: Elsevier Science & A ; Technology.


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