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freetronics / DMD2

Beta release of a new Dot Matrix Display Arduino library
http://forum.freetronics.com/viewtopic.php?f=26&t=5893
GNU General Public License v3.0
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Flickering of screen when more than 8 panels are connected #65

Closed pererasampath closed 3 years ago

pererasampath commented 3 years ago

DMD2 library use SoftDMD class instead of SPIDMD class. When number of panels exceed 8 a slight flicker starts and get worse when it crosses 14 panels. What I have noticed is that scandisplay get triggered from Timer1 overflow interrupt which further reduced by 50% to scan the displays. which results in about 4ms for the SCK signal. This time slot get filled with data when the number of displays exceed 8, which makes SCK signal to adjust to 6ms. This results the scanning frequency to get reduced from 60Hz to 40Hz, which resuts in the flickering. So wonder whether I should revert to SPIDMD library to avoid this.

pererasampath commented 3 years ago

I switched to SPIDMD library and matter was sorted. I have tested upto 20 panels with no flicker, even 30 should be ok.