I got parts from various places along with PCB made by PCB-pool.com using DesignSpark. PCB was the last item I was waiting on. The PCB worked as designed :-) (this thing was my 1st PCB design). Slow mail took a while to get to me from Ireland to have PCBs delivered. & I had to go to the post office to pick up the box on Saturday, since I was at work.
I was going to have 8 8x8 LED RGB matrix but that was going to be too big (read expensive PCB) and have decided on 4 matrix, giving 8x32 display. I now have to work on software side of this project and I feel like I can make it ok. Since I only have 4 (8x32) matrix, I can do 24bit color (8bit color per R/G/B) without any problems.
Only issue I had to resolve today and took while to fix was around DS1307. I was getting some strange error and I could not figure out why. It turned out to be some voltage issue with clock (DS1307), back up battery and my PSU. I am using old PC ATX PSU that provides me with 5V (4.91v says my DMM). My PCB design had a diode right after the power, which made 5v to drop around 4.3v (I don't remember exactly). For some reasons (probably bad PCB routing issue caused by my design), DS1307's vcc was around 4.1v (somewhere there). My battery was giving about 3.02v. 3.02 x 1.25 = 3.775
so I should be just fine but
??? Any case, I just removed (shorted) the diode I had and problem resolved
This is what datasheet for DS1307 says
When VCC falls below 1.25 x VBAT the device terminates an access in progress and resets the device address counter. Inputs to the device will not be recognized at this time to prevent erroneous data from being written to the device from an out of tolerance system. When VCC falls below VBAT the device switches into a low-current battery backup mode. Upon power-up, the device switches from battery to VCC when VCC is greater than VBAT + 0.2V
and recognizes inputs when VCC is greater than 1.25 x VBAT.
Now that all is working, I need to start getting software side working
more fun time to comehttp://www.flickr.com/photos/tokuro/sets/72157624989290204/
has more stuff...