PCB layout review

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I've just mede the layout for my IV-18 VFD project. The result is attached, including the schematic.
All components are on the top side.

Any hints on how to improve it?

Thank you,

Attachment(s): 

Felipe Maimon

Last Edited: Sun. Apr 25, 2010 - 06:25 PM
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Here is the schematic, as the forum only permits 3 attachmets per post.

Attachment(s): 

Felipe Maimon

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Can't really see details that well - a vectored image such as pdf or ps file may better reveal small traces. The LCD board (the one on the right) is routed on the same layer as the component. Are you still able to solder this easily? The same goes for the SMD - can you solder those? There are several floating pins in the schematic. I can't see them in the board images, but they should be tied to ground or Vcc.

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Nice job!

Be sure to post a photo of the completed project on the Projects Thread.

When I have a spare uC pin or two I usually bring it out to an LED and/or an easily reached test point, with a ground pin next to it. SMT LEDs are small, and can be used to indicate power, or a 1 Hz "heart beat", (the circuit is alive and running...). The Test point is useful for triggering a scope via software if you debug the "old fashioned way", (LED, Scope), not with JTAG, etc.

I would add a test point and ground for the V+ output, also.

I would suggest putting a version number and date on the board. Helpful if you ever revise it down the road.

JC

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Quote:

Can't really see details that well

You're not using IE are you? If so right click the image - use "copy image URL" then post that in a new tab - there's no problem reading the full size 1775x1040 image

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DocJC wrote:
Nice job!

Thank you.

DocJC wrote:
Be sure to post a photo of the completed project on the Projects Thread.

I have on when it was in the breadboard. It's attached.

DocJC wrote:
When I have a spare uC pin or two I usually bring it out to an LED and/or an easily reached test point, with a ground pin next to it. SMT LEDs are small, and can be used to indicate power, or a 1 Hz "heart beat", (the circuit is alive and running...). The Test point is useful for triggering a scope via software if you debug the "old fashioned way", (LED, Scope), not with JTAG, etc.

I would add a test point and ground for the V+ output, also.

I would suggest putting a version number and date on the board. Helpful if you ever revise it down the road.

It will be done :)
Thank you.

Attachment(s): 

Felipe Maimon

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clawson wrote:
Quote:

Can't really see details that well

You're not using IE are you? If so right click the image - use "copy image URL" then post that in a new tab - there's no problem reading the full size 1775x1040 image

I think he meant the layout pictures. They are not that good. Just updated the first post with pdf files.

Felipe Maimon

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tlucas wrote:
Can't really see details that well - a vectored image such as pdf or ps file may better reveal small traces.

First post updated.

tlucas wrote:
The LCD board (the one on the right) is routed on the same layer as the component. Are you still able to solder this easily? The same goes for the SMD - can you solder those?

Actually is a VFD, not an LCD... I'll be sending them to a board house, so all holes are going to be plated. I can solder SMD. They are quite easy to do.

tlucas wrote:
There are several floating pins in the schematic. I can't see them in the board images, but they should be tied to ground or Vcc.

All unused AVR pins are set to input with pull-up enabled, so I don't see any problem. To tie them to VCC or GND directly is asking for trouble if I accidentally short any pins while soldering.

FT232 datasheet says that inputs have a 200k pull-up, so no problem either and the only unused pin on the MAX6921 is an output.

Felipe Maimon

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I make unused pins outputs. TI recommends it for the MSP430, to reduce power consumption.

Leon Heller G1HSM

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Very nice! Even your mixed analog/digital grounds seem to direct the current correctly. I assume this will be send to a professional board house, seeing the many vias.

I'm intrigued by your PWM boost circuit. I assume that the pulses will be sufficiently short (inductor limits current) and/or the FET limits the current enough at 5V Vgs. Do you have a reference for this circuit? Then V+ goes to ADC0, I'm guessing as a feedback mechanism for the PWM...

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tlucas wrote:
Very nice! Even your mixed analog/digital grounds seem to direct the current correctly. I assume this will be send to a professional board house, seeing the many vias.

Yep. I think I'll go with Golden Phoenix...

tlucas wrote:
I'm intrigued by your PWM boost circuit. I assume that the pulses will be sufficiently short (inductor limits current) and/or the FET limits the current enough at 5V Vgs. Do you have a reference for this circuit? Then V+ goes to ADC0, I'm guessing as a feedback mechanism for the PWM...

It's just a plain vanilla boost circuit, controlled with feedback by the AVR (PI controller). The output voltage can be changed by the AVR in the range of 20-50 volts.

Nard (Plons) explains quite well all the workings on his website: http://www.aplomb.nl/TechStuff/S...

Felipe Maimon

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leon_heller wrote:
I make unused pins outputs. TI recommends it for the MSP430, to reduce power consumption.

That's quite easy to do... Just change/add a couple lines from initialization...

Felipe Maimon

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I'm sending the board to PCB International. I've found only a couple reviews and they were positive. Does anyone knows them?

Felipe Maimon