My first PCB design

[nobody554]

Originally posted by: roid450
say what?

QFT VVV

Originally posted by: zinfamous


sometimes I have no idea why I'm a member here.....


:beer:

It looks pretty ... I guess it looks good?

 

[alkemyst]

Originally posted by: Colt45
well, fair enough... but if there's room for thicker power / gnd, why not do it? same price either way

wow just wow.

 

[bobsmith1492]

I would do a ground plane pour on at least one side, probably both.

Route power, high-speed signal and clock lines by hand, at the least. Don't trust autorouters.

Otherwise it looks good to me. Don't forget about test points and silkscreen labels on your connectors - makes debugging much easier!

 

[zoiks]

Originally posted by: ganesh1

Originally posted by: Red Dawn

Originally posted by: ganesh1

Originally posted by: JMapleton
I'm glad I didn't major in computer science or electrical engineering like I wanted to.

iam just abt to enter engg
iam planning on taking electricals or computers or mechanical what do you guys think
which branch is the best iam cool with all branches except bio chemistry

Don't forget to include a couple of English clases.

WHATS WITH THE FUCKIN ENGLISH CLASSES
i speak good english , i just dont punctuate properly
blah soo what
iam a non native english speaker and a typer for peace sake

I recommend taking some English classes.

 

[Killmenow]

Originally posted by: ganesh1

Originally posted by: Red Dawn

Originally posted by: ganesh1

Originally posted by: JMapleton
I'm glad I didn't major in computer science or electrical engineering like I wanted to.

iam just abt to enter engg
iam planning on taking electricals or computers or mechanical what do you guys think
which branch is the best iam cool with all branches except bio chemistry

Don't forget to include a couple of English clases.

WHATS WITH THE FUCKIN ENGLISH CLASSES
i speak good english , i just dont punctuate properly
blah soo what
iam a non native english speaker and a typer for peace sake

Unless I am mistaken, having a competent level of written English is fairly important in engineering - mostly due to the numerous reports that one would be expected to write. Spoken English takes a huge sideline in favour of clear and effective written English, something which proper punctuation is vital for. A large percentile of my engineering class struggled with spoken English; however, so long as their reports were well written, it really didn't matter.

Personally, I would base my program selection on a few deciding key factors. Ask yourself what type of work you would be most interested in doing. Look into the various programs and their respective field of work to get a grasp of what you would be doing after you graduate as well the type of career that they can offer you (demand is also fairly important in this respect). Anywho, if you really are having trouble deciding on what to go for, then engineering might not be the best choice for you ;D~

 

[Red Dawn]

Originally posted by: geno

Originally posted by: Red Dawn

Originally posted by: ganesh1

Originally posted by: JMapleton
I'm glad I didn't major in computer science or electrical engineering like I wanted to.

iam just abt to enter engg
iam planning on taking electricals or computers or mechanical what do you guys think
which branch is the best iam cool with all branches except bio chemistry

Don't forget to include a couple of English clases.

:laugh:


Even if you did misspell "classes".

My typing sucks and it was before I had any coffee. In my mind I spelled it right

 

[Drako]

You should do ground fill on both the top and bottom layers, since it's only a two layer board.

 

[Taejin]

Originally posted by: ganesh1

Originally posted by: Red Dawn

Originally posted by: ganesh1

Originally posted by: JMapleton
I'm glad I didn't major in computer science or electrical engineering like I wanted to.

iam just abt to enter engg
iam planning on taking electricals or computers or mechanical what do you guys think
which branch is the best iam cool with all branches except bio chemistry

Don't forget to include a couple of English clases.

WHATS WITH THE FUCKIN ENGLISH CLASSES
i speak good english , i just dont punctuate properly
blah soo what
iam a non native english speaker and a typer for peace sake

YEAH I SPEAK ENGLISH WELL TOO!!!!!

 

[Modelworks]

I would put more space between the red lines that go around the center chip. Really close you may get crosstalk at high speeds.
Also would put ground planes anywhere there was room. Remember PCB making is a process that removes copper so their is no loss in leaving large areas that could work as ground planes to lower interference.

 

[Cogman]

Originally posted by: ganesh1

Originally posted by: Red Dawn

Originally posted by: ganesh1

Originally posted by: JMapleton
I'm glad I didn't major in computer science or electrical engineering like I wanted to.

iam just abt to enter engg
iam planning on taking electricals or computers or mechanical what do you guys think
which branch is the best iam cool with all branches except bio chemistry

Don't forget to include a couple of English clases.

WHATS WITH THE FUCKIN ENGLISH CLASSES
i speak good english , i just dont punctuate properly
blah soo what
iam a non native english speaker and a typer for peace sake

Your English in writing is poor, so I have some doubts as to the fact that you "speak good english".

I have all the respect for you to be able to learn a second language, I really do. I know it is a difficult thing to do. However, as an engineer, being able to WRITE proper English, punctuation and all, is essential.

We criticize your English because we love you. (And yes, it is fun.... but who said love couldn't be fun )

(iam is not one word, you either say I'm, or I am. If you want to exclude punctuation, Im would even be better then iam)

 

[Cogman]

Originally posted by: Modelworks
I would put more space between the red lines that go around the center chip. Really close you may get crosstalk at high speeds.
Also would put ground planes anywhere there was room. Remember PCB making is a process that removes copper so their is no loss in leaving large areas that could work as ground planes to lower interference.

Yeah, that was what I was noticing. That circular loop just looks like it is begging for trouble. Space it out more or see if you can eliminate it all together.

 

[Leros]

Originally posted by: Jeff7
What software is that? The grid and all is similar to ExpressPCB, but the font of the text isn't quite the same.

This is PCBArtist. I've used ExpressPCB before. They are comparable. I think PCBArtist is a little bit nicer though.

Originally posted by: slackwarelinux
Depending on how your board is being manufactured, I'd try for a bit more clearance between traces (I usually go for 14 mils, 8 ought to be enough for most stuff though). The bus near R6 is a bit scary. The traces in the upper left look a bit sloppy too

The minimum width for manufacturing is 7 mils, I went with 8 to be safe.

Originally posted by: herm0016
looks like you placed a few components and let eagle do the hard part. its more fun to do it all by hand...

I routed everything by hand. Why does everybody think I used an auto-router?

Originally posted by: RESmonkey
What does it do?

Its got a graphical screen, two rotary encoders, a few switches, and an accelerometer. Its going to be an Etch-A-Sketch / Pong / something else?

Its a last hurrah for a microcontroller class. We're all making neat things and having a little competition at the end. My idea was to have a handful of simple games using the same interface.

Originally posted by: dullard
[*]Since you have lots of empty spaces, why not silkscreen on a board name, what the board does, or at least your name and a revision number.

Basically, I'm nitpicky and bored.

No doubt its a bit sloppy.

I have silkscreened some text on there. I just had it turned off when I took this image.

Originally posted by: bobsmith1492
I would do a ground plane pour on at least one side, probably both.

Route power, high-speed signal and clock lines by hand, at the least. Don't trust autorouters.

Otherwise it looks good to me. Don't forget about test points and silkscreen labels on your connectors - makes debugging much easier!

Not allowed to do ground planes. My professors logic is that since we're noobs at this we might need to cut some traces and a ground plane makes that more difficult.

I didn't do an autorouter

We've got 5 test points to test the memory interface and I think I can easily latch on to components for the other necessary test points.

Originally posted by: Modelworks
I would put more space between the red lines that go around the center chip. Really close you may get crosstalk at high speeds.
Also would put ground planes anywhere there was room. Remember PCB making is a process that removes copper so their is no loss in leaving large areas that could work as ground planes to lower interference.

I've already sent it off for manufacturing. We're only operating at 2Mhz. Hopefully it will be ok.

 

[Shadow Conception]

What's it do?

 

[Leros]

Originally posted by: Shadow Conception
What's it do?

My thought when designing it was to make a digital Etch-A-Sketch.

Its got a graphical LCD screen, two rotary encoders, and an accelerometer so you can erase it by shaking it.

A screen and two knobs seems like it would lend itself to pong and maybe a few other games too.

 

[KMc]

There are a few right angle traces that I would clean up.

 

[blahblah99]

Originally posted by: Leros
I just finished designing my first PCB design. Two layers, no ground planes allowed. I was a bit rushed in the layout and the last traces I placed are in no way optimal routed. What do you guys think?

(one of the power wires isn't connected, ignore that for the moment).

First PCB Design

Details:
Archaic 6811 microcontroller (512 bytes ram and rom)
8k external eeprom
16 bit SPI I/O Expander
graphical LCD header
2-axis accelerometer
2 x rotary encoders
power supply
programming headers
low voltage reset

If you have analog signals I hope you didn't cross digital lines across it. Only reason why I mention it is because I dont' see a ground plane and you have an accelerometer. If the output of that is a PWM signal then all is good.

So if you get horrible noise on your analog circuitry, that's the main reason.

Other than that, the layout looks pretty straightforward. Use fatter traces for power signals, ground plane for ground. Even on a two layer board - try to route as much as possible on one layer and use the other as a ground plane.

That's my two cents. To some clients, its more than two cents.

 

[Leros]

Originally posted by: KMc
There are a few right angle traces that I would clean up.

Oops.

I ran power and ground around the edge of the board since I can't do a plane. I allowed right angles off of those.

 

[Leros]

Originally posted by: blahblah99
If you have analog signals I hope you didn't cross digital lines across it. Only reason why I mention it is because I dont' see a ground plane and you have an accelerometer. If the output of that is a PWM signal then all is good.

So if you get horrible noise on your analog circuitry, that's the main reason.

Other than that, the layout looks pretty straightforward. Use fatter traces for power signals, ground plane for ground. Even on a two layer board - try to route as much as possible on one layer and use the other as a ground plane.

That's my two cents. To some clients, its more than two cents.

The power/ground traces were 15 mils, I bumped them up to 25 mils.

I am using PWM off the accelerometer, so all should be good there.

 

[Colt45]

Originally posted by: alkemyst

Originally posted by: Colt45
well, fair enough... but if there's room for thicker power / gnd, why not do it? same price either way

wow just wow.

wow what?

 

[Analog]

Without a schematic, I don't know what's what. But we always manually run the analog traces first, especially with ADCs. This gives them priority, so they're not convoluted. Then sometimes we put in either guard traces around them, or route the digital stuff on a different plane at right angles. Sometimes we separate them with a ground plane. I know you can't do the latter, but take a close look at your ADC input traces. Make sure their short, direct and not adjacent to noisy digital lines. You'll thank me for that after its all said and done. Most of our ADCs are 16 bit and above though. I have no idea what resolution or voltage range you're looking at. The use of decoupling caps is good. I would also recommend a tantalum (~10-20uF) in parallel with a 0.1uF ceramic at the power entry point on the board.

 

[Leros]

Originally posted by: Analog
Without a schematic, I don't know what's what. But we always manually run the analog traces first, especially with ADCs. This gives them priority, so they're not convoluted. Then sometimes we put in either guard traces around them, or route the digital stuff on a different plane at right angles. Sometimes we separate them with a ground plane. I know you can't do the latter, but take a close look at your ADC input traces. Make sure their short, direct and not adjacent to noisy digital lines. You'll thank me for that after its all said and done. Most of our ADCs are 16 bit and above though. I have no idea what resolution or voltage range you're looking at. The use of decoupling caps is good. I would also recommend a tantalum (~10-20uF) in parallel with a 0.1uF ceramic at the power entry point on the board.

Well, I ended up connected my accelerometer with the PWM outputs instead of the analog outputs anyway. I realized I was going to need an op-amp on the analog output since you can't have a capacitive load on an ADC input. Instead of adding more circuitry, I just used the PWM outputs instead.

 

[zinfamous]

Originally posted by: ganesh1

Originally posted by: Red Dawn

Originally posted by: ganesh1

Originally posted by: JMapleton
I'm glad I didn't major in computer science or electrical engineering like I wanted to.

iam just abt to enter engg
iam planning on taking electricals or computers or mechanical what do you guys think
which branch is the best iam cool with all branches except bio chemistry

Don't forget to include a couple of English clases.

WHATS WITH THE FUCKIN ENGLISH CLASSES
i speak good english , i just dont punctuate properly
blah soo what
iam a non native english speaker and a typer for peace sake

see, there you go again. :laugh:

like we've mentioned before, it's great that you're non-native, just don't claim you are great, good at something when all the evidence at your disposal works against you.

look, you're non-native, so there's no reason for anyone to expect that you would even know "good English."

 

[IEC]

Originally posted by: geno

Originally posted by: Red Dawn

Originally posted by: ganesh1

Originally posted by: JMapleton
I'm glad I didn't major in computer science or electrical engineering like I wanted to.

iam just abt to enter engg
iam planning on taking electricals or computers or mechanical what do you guys think
which branch is the best iam cool with all branches except bio chemistry

Don't forget to include a couple of English clases.

:laugh:


Even if you did misspell "classes".

intentional

 

[So]

Originally posted by: zinfamous

Originally posted by: ganesh1

Originally posted by: Red Dawn

Originally posted by: ganesh1

Originally posted by: JMapleton
I'm glad I didn't major in computer science or electrical engineering like I wanted to.

iam just abt to enter engg
iam planning on taking electricals or computers or mechanical what do you guys think
which branch is the best iam cool with all branches except bio chemistry

Don't forget to include a couple of English clases.

WHATS WITH THE FUCKIN ENGLISH CLASSES
i speak good english , i just dont punctuate properly
blah soo what
iam a non native english speaker and a typer for peace sake

see, there you go again. :laugh:

like we've mentioned before, it's great that you're non-native, just don't claim you are great, good at something when all the evidence at your disposal works against you.

look, you're non-native, so there's no reason for anyone to expect that you would even know "good English."

"good english"

Keep it classy, San Diego.

Also, punctuation has meaning.

http://en.wikipedia.org/wiki/Comma_(punctuation)

I spoke to the boys, Sam and Tom.
I spoke to the boys, Sam, and Tom.

Dropping the comma makes it into two completely different sentences. Not to say that I'm not an abuser of commas, but I don't claim that I'm perfect.

 

[TecHNooB]

3 years of undergrad and I still don't know shiiiiit.