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Author Topic: yet another TLC5940 (TLC5941) project...  (Read 1746 times)
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i am totally new to Arduino world.  i am testing out some idea from scratch so that i can really understand what it can do.  i understand that there's a nice LIB for 5940 but i wanted to do everything myself to learn the hard way.  Since 5941 was a bit cheaper, i am using 5941 instead of 5940.

My end goal is to have 16 x 32 RGB matrix display with a clock or something.  Due to memory limitation, i don't think i can have full set of colors with 16x32 but i should be able to do 16bit color (maybe 15 (3 x 5bits).  At least that's my goal.   smiley-wink

i got it to work with 8x32 in Red/Green LED matrix.  I only have green wired so far.  I have to setup 2 more 5941 to wire up Red LEDs.  With just 1 color, i do have full 12bit brightness control and can address each pixles (like VGA frame buffer)  I did somewhat simulated 6 TLC5941 scenario and i think i can make it.  

I have 74HC595 to drive/switch rows and TLC5941 and TLC5940 (yes, one each).

this is going to be a slow project since i do have a day job and playing Halo Reach here and there...

just wanted to say hello to the community....  :smiley





http://www.flickr.com/photos/tokuro/5005074570/ for a bigger photo.
« Last Edit: September 19, 2010, 12:09:08 pm by tokuro » Logged

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Very good - hope you have lots of jumper wires smiley-wink
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An update...

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…

Quote
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 come



http://www.flickr.com/photos/tokuro/sets/72157624989290204/ has more stuff...
« Last Edit: October 25, 2010, 01:51:03 am by tokuro » Logged

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How is the project coming along? Have you found any substantive difference between the TLC5940 and TLC5941?
« Last Edit: December 30, 2010, 12:58:31 am by isnoop » Logged

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you can use 5941 and 5940 the same way with a few things to remember.  5941 can handle up to 80ma where 5940 can take 120ma.  5941 does not have EEPROM for DC so you need to set it up at the first (one time setup).  You do have to setup DC on 5940 also but have an option to burn DC info on ROM and use that as default.  If you make your code to setup 594x DC at first, your code will work on both chips.  Other than those, they are identical and 5941 should be cheaper for you (most cases).

I'm done with what i wanted to do and is working great.  if you have any questions around 5941, pls feel free to ask.  :-)

« Last Edit: December 30, 2010, 11:27:41 am by tokuro » Logged

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