Upverter layout - Arduino clone "the shrimp" - Page 1
Forum section: electronics / beginners

author: MichaelW
author_rank: Contributor
timestamp: October 19, 2013, 02:13:58 pm
content: I found this site, which I'm sure you are all aware of already, that has a schematic for an arduino clone called "the shrimp". I built a couple on a breadboard and finally got it to work, then progressed to making one on a piece of perfboard. Wow, was that tedious and annoying. Finally, I got some stripboard and made a couple that didn't work (not sure why, I'm sure I did something stupid) before I made a third that did.So, I figured it'd be fun to try to layout my first PCB with that project in mind.https://upverter.com/MWilliams/1e4204bf3e679cb3/Shrimp/If anyone has any tips/pointers/critique I welcome them! Upverter is pretty cool, and apparently fairly newbie friendly. :-) I'm sure I missed things and that this isn't a viable board.Oh, I wanted to add some screw holes at the corners for mounting, but I couldn't figure out how.

author: EnZz
author_rank: Newbie
timestamp: October 22, 2013, 04:49:47 pm
content: Hi Michael,You should open a design review for your design. Other hardware hackers could then take a look and comment on your schematic and layout designs!If you need any help regarding the tool itself, feel free to shoot us an email at support@upverter.com, Anandh and the team will be happy to help.CheersEnzo

author: JoeO
author_rank: Frequent Contributor
timestamp: October 22, 2013, 05:29:57 pm
content: This is NOT an Arduino clone. It is a minimal 328 board.

author: senso
author_rank: Frequent Contributor
timestamp: October 22, 2013, 08:24:04 pm
content: Its an atmega, 4 caps, a button and a couple headers...

author: MichaelW
author_rank: Contributor
timestamp: October 24, 2013, 12:54:57 am
content: Haha, yea, fair enough, it doesn't have most of the stuff that makes and Arduino an Arduino besides the chip and the bootloader.Give us newbies a break, huh? :-)Ok, I hope I did did the review thing correctly:http://upverter.com/eda/#designId=1e4204bf3e679cb3,reviewId=d7cc615dfab1c1ea,tool=schematicIf anyone wants to offer suggestions. :-)

author: JoeO
author_rank: Frequent Contributor
timestamp: October 24, 2013, 01:17:17 am
content: C7 is wrong. It needs to go between on leg of the crystal and ground.

author: free_electron
author_rank: Super Contributor
timestamp: October 24, 2013, 01:20:31 am
content: PLEASE make decent schematics ok ? this is total and utter CRAP.scattering some random parts and throwing netnames on em is not a schematic !as for the pcb layout ... almost all footprints are wrong !and your schematic has mistakes too. remove that cap across the crystal !

author: c4757p
author_rank: Super Contributor
timestamp: October 24, 2013, 01:33:22 am
content: Join your grounds! What in the name of all that is good are "GND8" and "GND22"? And how is AVCC supposed to get power, leakage currents across the solder mask?

author: MichaelW
author_rank: Contributor
timestamp: October 24, 2013, 01:54:59 am
content: Ok, I hear you guys loud and clear! That travesty is gone from the internet. :-) I'll learn more and try something else later on when I can offend people less with it. hah.

author: c4757p
author_rank: Super Contributor
timestamp: October 24, 2013, 02:21:01 am
content: Dude, it's just an AVR and some crap... fix the problems we've said and it'll be fine. Don't give up, that's how youavoidlearning.To clarify what's been said:1) There are a number of dumb mistakes to be made with oscillators - I strongly suggest you build up a simple crystal oscillator of the type used in the AVR, and play with things like the load caps. (The AVR uses a digital inverter connected across the crystal, that's about the simplest crystal oscillator you can build. Input to one side, output to the other.)Playing with crystal oscillators is one of the good uses for a higher bandwidth scope, if you can get your hands on one. It's nice to see the true shape of the wave. But even a 20 MHz one will show the frequency.2) Labels are not an acceptable way to make connections in a schematic like that. They make it hard to figure out what's connected to what. They can be used with care in a few situations, especially to make connections from one sheet to another (the software will usually have a dedicated tool for this purpose), but using them to join a crystal to a pin (that resides about an inch away) is just wrong. Otherwise, use labels to mark existing wires to give hints about their purpose.3) All the ground pins on the chip must be connected together.4) All the power pins on the chip must be connected together.