Port-A-Prop PCB
Painless
Posts: 69
I'm working on designing a PCB that will allow me to take a DIP prop and EEPROM around with me very conveniently, while also providing access to I/O pins, a crystal and PC access via a prop clip. I intend to use IC sockets for the Propeller and EEPROM so that they can be easily replaced if necessary.
I should mention that while I'm not entirely new to electronics, this is the first PCB I have ever attempted to make and would really appreciate any advice / recommendations anyone may have before I spend money having some PCB's made. Also, if anyone can recommend a PCB service that is suitable for a very small number of PCB's I would appreciate it, ExpressPCB is expensive!
I have attached a picture of the PCB as well as a copy of the .PCB file.
Many thanks in advance,
Russ.
I should mention that while I'm not entirely new to electronics, this is the first PCB I have ever attempted to make and would really appreciate any advice / recommendations anyone may have before I spend money having some PCB's made. Also, if anyone can recommend a PCB service that is suitable for a very small number of PCB's I would appreciate it, ExpressPCB is expensive!
I have attached a picture of the PCB as well as a copy of the .PCB file.
Many thanks in advance,
Russ.
Comments
It might come in handy to also include pins A30 and A31. That would provide access to all the pins.
And maybe have power on a separate header. Maybe a power ON/OFF switch, rather than pulling a plug.
My 2¢ worth.
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Harley Shanko
Don't forget the decoupling Caps.
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Sorry for the quick reply. Probably not appropriate, but given the posts over the last 24 hour about caps...
It is a nice design Russ. Worthy of nice simple protoytyping. I would have one or two in my laptop bag.
Post Edited (hover1) : 6/20/2009 1:28:19 AM GMT
Looks Ok.
But not forget decoplings caps.
One thing all forget that I2C can drive more that only Porgram loading EEprom.
Have them out of PCB to
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Nothing is impossible, there are only different degrees of difficulty.
For every stupid question there is at least one intelligent answer.
Don't guess - ask instead.
If you don't ask you won't know.
If your gonna construct something, make it·as simple as·possible yet as versatile as posible.
Sapieha
I've made some changes (new PCB attached):
1) Access to pins 30 & 31.
2) Moved Vss & Vdd to a separate 2 pin header.
3) Added two decoupling caps, a 100uf electrolytic and a 0.1uf ceramic.
4) Fixed a few errors I noticed with crossed tracks.
I may add the reset switch, but for now want to keep the PCB simple.
Thanks again!
Russ.
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Links to other interesting threads:
· Home of the MultiBladeProps: TriBladeProp, SixBladeProp, website (Multiple propeller pcbs)
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: Micros eg Altair, and Terminals eg VT100 (Index)
· Search the Propeller forums (via Google)
My cruising website is: ·www.bluemagic.biz·· MultiBladeProp is: www.bluemagic.biz/cluso.htm
can You post printed version of that layaut.
I not have posiblites to wiev Yours PCB file
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Nothing is impossible, there are only different degrees of difficulty.
For every stupid question there is at least one intelligent answer.
Don't guess - ask instead.
If you don't ask you won't know.
If your gonna construct something, make it·as simple as·possible yet as versatile as posible.
Sapieha
Here's a bitmap of the layout in ExpressPCB.
Russ.
Russ.
Do not use right angled tracks - use 45 degree bends. Two reasons, one is because it makes pcb manufacture easier (as in etching issues) and secondly because it sharp corners radiate more emi (rf interference).
Use thicker xtal tracks. For future reference, always keep as short as possible.
Your ground track is still to thin from the prop. You could just place a thick track from the cap near the xtal to the Vss track on the top side (red). I would have run two thick vertical tracks under the prop for power and ground (see my TriBlade board picture) and place a tantalum capacitor directly under the prop chip which can be soldered on the underside of the pcb if required for overclocking (an extra one).
A pullup resistor should be on both the SCL and SDA lines of the EEPROM. While this is not absolutely necessary because of the way the prop loads it's code, other code might use tristate instead of driving SCL.
Power supply: What regulator are you using (pinouts vary and the LM1086 and LM1117 are different to what you have used)? As previously stated, you will reauire a 47uF to 100uF 25V electrolytic on the input power for filtering and likewise recommend a 1N4001 or 1N4004 diode to protect against reverse voltage. The power connector disconnects the gnd pin when plugged in - so you need to either join the other power plug pin to gnd or move it from the side pin to the unused pin. A power switch is nice but not mandatory (see my TriBlade parts list for a DigiKey switch).
Attached is Blade #3 section of my TriBlade. It may give you a few ideas. Note I mount the 2 pullup resistors and the eeprom on the underside of the pcb (so it is a mirror image).
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Links to other interesting threads:
· Home of the MultiBladeProps: TriBladeProp, RamBlade, TwinBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: Micros eg Altair, and Terminals eg VT100 (Index) ZiCog (Z80), MoCog (6809)
· Search the Propeller forums (via Google)
My cruising website is: ·www.bluemagic.biz·· MultiBladeProp is: www.bluemagic.biz/cluso.htm
Post Edited (Cluso99) : 6/21/2009 7:22:26 AM GMT
I have a DemoBoard in an old tape case for road use.
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Style and grace : Nil point
Its a nice layout, great for travel.
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Toys are microcontroled.
Robots are microcontroled.
I am microcontroled.
If it's not Parallax then don't even bother. :-)
Propeller SRAM TV driver winner: ==NOT COMPLEATED:·2 1/2·WEEKS UNTIL ENDING TIME==
Double check the power supply traces to the Propeller, I think you have one side of the prop's supply pins reversed.
Lawson
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Lunch cures all problems! have you had lunch?
Reset button as well? Slowly it'll become a demoboard?
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Style and grace : Nil point
I'm planning on using the LM2937 3.3v regulator for the board, the pinout is IGO.
Thanks for everyones input once again, I'm about to start working through the suggestions and applying them to the project.
What I'm trying to achieve here is an easy way to be able to program and develop without having to lug my PropRPM board, serial cable and other bits and pieces around with me. I would be really happy if I could design a 'fits in your pocket' solution, with all my source code on a USB key.
I'll post an updated layout soon.
Russ.
You're right! I just fixed that, thanks!
Russ.
These are the changes:
1) Added caps to power input before regulator.
2) Changed power jack to a 2 pin header for more versatility and space.
3) Added a power LED.
4) Added a power switch.
5) Added option for a tantalum capacitor underneath the prop.
6) Pullup resistors on both SDA and SCL lines.
7) Labels moved to the silk screen layer.
8) Included header mount to enable use of both the PropClip and PropPlug.
9) Fixed the power line mistake as per Lawsons post.
10) Added a protective diode to the power input.
11) Thick ground / vdd tracks for the prop.
I want to thank everyone once again for their guidance, suggestions and patience!
Can anyone recommend a service for having a small amount (less than 5) of these made without breaking the bank?
Russ.
If posible place all signal traces away from Crystal.
Place Yours power rails on other side of prop and place signal traces betwen with more space from Crystal
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Nothing is impossible, there are only different degrees of difficulty.
For every stupid question there is at least one intelligent answer.
Don't guess - ask instead.
If you don't ask you won't know.
If your gonna construct something, make it·as simple as·possible yet as versatile as posible.
Sapieha
I suggest to try the free EAGLE-version. (<www.cadsoft.de>)
Don't use the autorouter. In Eagle, you can click on a track and highlight the whole signal. Then you see what you can improve. It also checks for clearances.
Think of layout being just an other kind of maze.
I attached a **quick** scribble of what came to my eye. It is *not at all* complete!
Make the connections to the X-Tal as short as possible. No signals beneath it. You'll have to move the x-tal down a bit.
Vdd is not routed good. Look what bends it has to make. You can trace one signal between pins, So the Vdd gets a much shorter connection.
Placing C5 and C6 side by side doesn't make much sense.
OK, this layout is bad. It takes longer to correct the errors than to start from new. Sorry! Use a better program.
There's a PDF about PCB-layout. Wait ... it is named "PCBDesignTutorialRevA.pdf" maybe Google finds it for you.
Edit:
Parallax-server is timing out when I try to upload the file. I'll try again tomorrow ...
HTH,
Nick
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Never use force, just go for a bigger hammer!
The DIY Digital-Readout for mills, lathes etc.:
YADRO
Post Edited (Nick Mueller) : 6/24/2009 10:41:10 PM GMT
Good progress so far.
If I have downloaded the .pcb file intact, your dimemsions are 1.5" x 2.65". If you could shave .15" off the vertical, you could fit two boards onto an ExpressPCB Miniboard, and you could get 6 boards (three MiniBoards) for $51.00 ($8.50 each). Is that the price point you were looking for?
Jim
I'm not sure what you mean about using a better program. This is his first PCB design and he just needs a method to draw a trace between Point A and Point B and produce a PCB. If he uses ExpressPCB or Eagle or Red/Blue tape, he would have arrived at the same design.
Russ just needs help with·some layout parameters.
I agree it needs somes tweaking in the xtal area.
I have found ExpressPCB to be·great for my projects, but have just downloaded Eagle for a try, since it's getting a lot of praise.
I agree; http://www.alternatezone.com/electronics/files/PCBDesignTutorialRevA.pdf is a must read. Thanks for that one Nick.
Jim
·
Files attached, comments / recommendations still very welcome.
Russ.
That is a much better layout.
I hope you have learnt a lot and have not been put off by our recommendations
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Links to other interesting threads:
· Home of the MultiBladeProps: TriBladeProp, RamBlade, TwinBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: Micros eg Altair, and Terminals eg VT100 (Index) ZiCog (Z80), MoCog (6809)
· Search the Propeller forums (via Google)
My cruising website is: ·www.bluemagic.biz·· MultiBladeProp is: www.bluemagic.biz/cluso.htm
I most certainly haven't been put off, I've learnt a ton here and am extremely grateful for all the input and recommendations.
I've implemented your suggestions, hopefully I've understood them correctly. I had to rename the extension for the pcb file to pcb-layout as for some reason the upload manager refused to accept that file type this time.
Russ.
WOW! Man, you got it! *clapclapclap*
Now for the nitpicking:
The cap underneeth the Prop. Oh, you'll have a socket, then that woks.
Some traces are still to close together. With all that nice layout, you can use copper-pouring on the top or bottom for the Gnd-signal.
Again, try EAGLE. It has its drawbacks, but you'll like it. But most of all, it has an DRC (Design rule check; for layout) and an ERC (electrical rule check; for the schematics) that helps a lot to avoid (stupid) errors.
Didn't look too close to it, but:
It is sooooo much better then the previous layout.
You'll *always* find a better route *after* the board is etched.
Edit:
Had a closer look:
Again, you made a **huge** progress!
I'd move the voltage regulator a bit to the right to make room for the resistor near him.
I've attached a corrected bmp with my suggestions. As I don't have the original schematics, I might have overseen something.
The green trace on the top edge near Gnd/Rst is too close to the vias.
The reason why I changed the layer for the green trace underneeth the Prop is for better copper pouring.
The Rst-line needs a pull-up resistor (4..10k)!
You can leave out C5, it's too close to C4 to be of big use.
Nick
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Never use force, just go for a bigger hammer!
The DIY Digital-Readout for mills, lathes etc.:
YADRO
Post Edited (Nick Mueller) : 6/25/2009 7:13:14 AM GMT
Now, Nick has actually picked up an error in the ground trace going to pin 5 of the eeprom round the loop. His rerouting led me to see this. If a socket is always going to be used, the eeprom can actually be placed under the prop within the socket on the same side of the pcb.
I would re-reout the power and ground from the eeprom to the top of the pcb. Use the same idea for 2 thick tracks under the eeprom. Move C3 to the other end of the eeprom and then you can route pin 1 to pin 7 around the top. Just use small traces from pin 4 to 3, 2, 1 and 7 as these are not power pins. Same with the prop pin 10.
Also I suggest you swap the unlabelled cap with R1 and move the regulator for more room as Nick suggested.
The holes for the eeprom are too close to the edge of the pcb. Nothing can be within 0.25" and preferably 0.50" of the pcb edge.
Looking further at the pcb, I think I would like to see 3 caps under the prop so turn vertical. The 2 caps closest to the prop power pins should be 100nF and the cap in the middle should be 10uF to 47uF tantalum. This will put you in a good position for overclocking.
You almost have a single layer design, so you could make links for this. However, a single layer is harder to solder.
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Links to other interesting threads:
· Home of the MultiBladeProps: TriBladeProp, RamBlade, TwinBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: Micros eg Altair, and Terminals eg VT100 (Index) ZiCog (Z80), MoCog (6809)
· Search the Propeller forums (via Google)
My cruising website is: ·www.bluemagic.biz·· MultiBladeProp is: www.bluemagic.biz/cluso.htm
It is mutch beter. But Have always traces go in another with 90 degres angle
Have always 45 graders on bends
If posible not conect lines direct to vias/pads with angle.
I have marked only 2 of Yours PCB's places that You can draw beter but it is that places much more.
Look on my picture.
Ps. It is only addition's to what others said
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Nothing is impossible, there are only different degrees of difficulty.
For every stupid question there is at least one intelligent answer.
Don't guess - ask instead.
If you don't ask you won't know.
If your gonna construct something, make it·as simple as·possible yet as versatile as posible.
Sapieha
Post Edited (Sapieha) : 6/25/2009 9:50:13 AM GMT
Cluso:
I like the idea of being able to put the EEPROM under a socketed Propeller chip, however, I plan to use sockets for both the EEPROM and the Propeller, plus, I want to be able to switch out EEPROM's for batch programming and may even use a ZIFF at a later date.
Nick:
I downloaded Eagle last night and had a look at it, it does seem to be a very capable program although there is a learning curve associated with it. I think I will stick with ExpressPCB for the moment and take a deeper look at Eagle later.
Cluso & Nick:
Unless I'm misunderstanding, it seems that you have different opinions reference multiple capacitors in close proximity around the circuit? As far as I can see, the idea is to have a larger and a smaller cap together so that the smaller cap can respond more quickly to power needs and the larger cap can provide longer term requirements for power? Both caps should also play a part in reducing IC noise?
Hover:
Your idea of fitting two boards onto one is a good idea for saving money. I'm on a very low budget (aren't we all right now?) and am shooting for making my first board myself, hence trying to keep it to a single side design with a few small jumpers.
Once again, thanks for everyones advice.
Russ.
Near Ok.
Only one thing I am misung.
Caps near Reg on Outgoing side,
100nF and 10-47uF
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Nothing is impossible, there are only different degrees of difficulty.
For every stupid question there is at least one intelligent answer.
Don't guess - ask instead.
If you don't ask you won't know.
If your gonna construct something, make it·as simple as·possible yet as versatile as posible.
Sapieha