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My first PCB design

Leros

Leros

Lifer
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


Edit:

Updated PCB

I got a better LCD, so I changed the LCD header wires a bit.

I was using analog out from the accelerometer, then realized that I can't hook up a capacitive load to an ADC directly, so I just used the PWM output instead.

I also fattened up the power wires from 15 mil to 25 mil.

This got sent off to manufacturing already. It could use some changes, but I think it will be ok.
 
I've got this mental thing, where I try and make every trace as fat as possible, within reason. i dunno.

Especially power and ground.. they look a lot lighter than I like on this one. Nice to slap a 0.1uF or so near the rails for every IC too, looks like you got some, but maybe a few short..
 
Originally posted by: Colt45
I've got this mental thing, where I try and make every trace as fat as possible, within reason. i dunno.

Especially power and ground.. they look a lot lighter than I like on this one. Nice to slap a 0.1uF or so near the rails for every IC too, looks like you got some, but maybe a few short..
Click to expand...

My power and ground are 15 mil, my signal wires are 8 mil. Should be plenty by my calculation.

Every IC has a 0.1uF cap on the rail.
 
If the device is sensitive to noise (doubt it), put one leg of the decoupling caps into the holes for the rail pins.
 
well, fair enough... but if there's room for thicker power / gnd, why not do it? same price either way 😉
 
Looks about like the ones I've designed. I agree with Colt45 that I tend to beef up Vcc / Gnd even though I never do any calcs to check if they are necessary (granted the PCBs are for me or for class projects, not production).
 
Originally posted by: JMapleton
I'm glad I didn't major in computer science or electrical engineering like I wanted to.
Click to expand...

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

 
Originally posted by: JMapleton
I'm glad I didn't major in computer science or electrical engineering like I wanted to.
Click to expand...
...and we are glad that we did!

Nice looking PCB! Grounding plains make it so much easier.
 
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
Click to expand...


It looks uh... (checks adjective of the day calander)... viridescent
 
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.
Click to expand...

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

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

:laugh:


Even if you did misspell "classes". 😉
 
I am glad that even though I slaved my self to become a micro electrical engineer....I ended up doing macro electrical engineering.
 
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 😛
 
looks like you placed a few components and let eagle do the hard part. its more fun to do it all by hand...
 
Originally posted by: edro
Originally posted by: JMapleton
I'm glad I didn't major in computer science or electrical engineering like I wanted to.
Click to expand...
...and we are glad that we did!
Click to expand...

I wish I didn't major in EE as now I have a piece of paper for something I don't necessarily want to do 🙁
 
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.
Click to expand...

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

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

 
Looks like fun. I have no training in electronics or PCB design, but I've made about 10 PCBs for work for different projects. I always am thrilled to start another board.

Good job on a first board. Again, since I have no training, I can only go from recommendations I've read in books/online. But my thoughts are:
[*]Why such thin traces? Sure they can probably handle your current, but why bother risking complications from such thin traces? And thin traces are bad for the environment (nasty chemicals have to eat away all that copper).

[*]Why place the traces so close to the board edge? I'm thinking about the right hand and bottom sides. Your board could have been smaller if you moved those traces in.

[*]Good job on making the mounting holes periodic. I hate building a machine and realizing that the PCB designer put the holes in random places. I makes it much easier to make the mounting plate if the holes are in regular locations.

[*]The connection from U3 to WE is quite sloppy. Connect C9 to U3 with a blue line instead of red, and then you'd have a direct connection from U3 to WE.

[*]You used a lot of unnecessary vias and placed them under components. While that will probably work, you are just making the board weaker and more difficult to debug. For example, look at U3. There are three vias under it that could easilly have been to the bottom or left of it. And the via to the right of U3 could be eliminated by just bringing the wire from the top right pin on U2.

[*]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. I have dozens of different PCBs laying around for work, my own and others, and it would be confusing if they weren't labeled. Sure, this will be your first, but it probably wouldn't be your last.

Basically, I'm nitpicky and bored.
 
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.
Click to expand...

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

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
Click to expand...

For the sake of peace, LEAVE THIS MAN AAAALOOOOOOOONE!!!!!!!
 
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