You should find the Data Sheet when looking up the part number on the DigiKey web site or perhaps the Micrel web site. The Micrel MIC5821 and MIC5841 are almost identical to the Allegro A6821 and A6841 devices.
I'm not aware of higher density serial-to-parallel high-current sinking drivers. If you find some, please let me know? Thanks.
I built a 10x7 led signboard using PIC16f84a.just to get some experience in making moving signs.It consist of count down,scaning from left & right,hold on display,elevator method,adding letters......etc.
Ok, it's what I was understanding. From my point of view, this solution is too time consuming and can leads to errors (their is no direct link between schematic and PCB), but, you probably have reasons to do so!
More positively: your schematics look better than any one made from a commercial package!
You should use something like Eagle for the crude start out trace, learning to use it is smarter than learning to place manually yourself. After it's placed it's traces you can tweak them to your hearts content. Doing the whole thing from start to finish on your own is really a waste of time, no matter how good you get at it.
Ya MS Office Packages does a great job also MS Paint.We wont consider much of these built in tools we mostly Prefer to advanced schematic design softwares. In my case I Preffer MS Excel for Schematics.It's So fun & very Creative.In the begining it takes some time to draw & after having experience can work quickly.
Thankx Mike for ur coloured Schematics.It's very useful.
Someone uploaded that EPE "Giant LED Message Display" article on EDAboard in this thread; **broken link removed**
The Author actually did a very nice job coming up with a cohesive comprehensive 'system' for driving 5x7 matrix display modules. The design doesn't include row drivers and can't drive the displays to full brightness and doesn't include PWM brightness/fade control but is nonetheless a reasonably well thought out design.
I built a 10x7 led signboard using PIC16f84a.just to get some experience in making moving signs.It consist of count down,scaning from left & right,hold on display,elevator method,adding letters......etc.
Unfortunately I coudn't find any led matrix so I used normal 5mm led's.no mo memory space in the pic to add more patterns only 2 lines left in program memory.