Hey guys! I thought I would ask the PROs before etching this out on double-sided PCB (see image at bottom).
It's a very basic design for a clock that's based on the ATTiny85 and takes advantage of the DS1307 for time-keeping. I'm not sure what my problem has been in the past where I have not been able to get such a simple thing running (the ATTiny85 and LCD have worked fine, but not the DS1307). I think it has to do with buying cheap DS1307s from eBay but finally I ordered some from a reputable website (at a price).
The DS1307 ($3.75) will arrive later in the week so I want to make sure my design will work before frying the poor thing. What I have done differently with the following PCB design is adding a ground plane for the first time and especially in-between the digital lines.
Can any of you PROs out there quickly review my design and tell if you see any mistakes?
Buying cheap saves money but can waste time and end up costing more in the long run (doesn't hurt to try though, right?) LOL
So I'm going to have the thing powered by a Micro-USB adapter and have a line running through the board supplying the 5V to the different components.
A ground-plane will ground the components to ground and be used to minimize noise in-between the I2C lines as I have had problems with it before (I'm pinpointing it to cheap chips).
My main worry considering that I know the LCD and ATTiny85 work properly when using I2C is having the DS1307 properly connected. I have read in other posts that I should have the crystal grounded (which I have done in this layout) and to add a .1uF capacitor to 5V on the DS1307 (I have yet to do so.)
I'm basically going to have a 20x4 LCD at around 45deg on the upper-portion (with it's potentiometer sticking up on the left) and a 6 button interface at 0deg on the bottom-portion covering the whole thing.
Thanks for your help! I wish to provide the PCB artwork and schematics to the public on my website if it turns out to be a success.