wackazong Posted September 1, 2008 Report Share Posted September 1, 2008 Hi,I am in the process of making (and soon hopefully documenting...) a button matrix of 256 buttons, each one with its own RGB LED, which can be controlled via MIDI. At the moment I am wondering whether it would be possible and feasible to route 256 digital inputs via DIN-Modules into one core. I can control 256 LEDs with one core (via I2C, working beautifully), the maximum number of 128 digital inputs would be the only reason that I need another core and the MBLink feature. I am shure this would work, but it would mean more systems, more interfaces, and more hardware. I cannot easily use a button matrix because of the modular setup of my pcbs, the matrix is more complicated regarding routing, and my routing is already very complicated (I am already forced to use a 4-layer pcb). So, if it is possible and can be done with acceptable latency (>100Hz) then I would like to reprogram the corresponding MIOS routine to support 256 buttons. Any tips for me? Thanks!ALEXander. Quote Link to comment Share on other sites More sharing options...
stryd_one Posted September 1, 2008 Report Share Posted September 1, 2008 Honestly... I would chalk that up to experience, and design new PCBs to use a matrix. There are numerous ways around it but ahh... I don't recommend jury rigging things. 7 Workaround != fix Quote Link to comment Share on other sites More sharing options...
wackazong Posted September 1, 2008 Author Report Share Posted September 1, 2008 Well, wouldn't it just be increasing the counter of the serial shift register inputs to 256? Or am I completely wrong here?ALEXander. Quote Link to comment Share on other sites More sharing options...
DrBunsen Posted September 1, 2008 Report Share Posted September 1, 2008 You might want to have a look at what I just posted in The Official Ebay Thread Quote Link to comment Share on other sites More sharing options...
wackazong Posted September 1, 2008 Author Report Share Posted September 1, 2008 To explain my situation, why redesigning the pcb does not make much sense:I have a pcb which supports 16 buttons and 16 rgb leds. The 16 buttons are connected to a DIN module with two shift registers. This pcb is intended to be chained together to form a button matrix of almost any (well, up to 256 buttons it should be) size. If I use the normal DIN concept, I just need three wires running from board to board, which is extremely convenient. This would not be possible with a matrix solution.So, what do you think I should do in this situation?Thanks, ALEXander. Quote Link to comment Share on other sites More sharing options...
bugfight Posted September 1, 2008 Report Share Posted September 1, 2008 ...So, what do you think I should do in this situation?...if you put your shift registers on the pcb, you only need 6 wires.i did this on the sparkfun duo matrix pcb... Quote Link to comment Share on other sites More sharing options...
wackazong Posted September 1, 2008 Author Report Share Posted September 1, 2008 OK, but three wires is better than 6, right? I have two other wires for I2C already, and I need to connect a lot of modules, therefore I think to reduce EMI and all that it would be good to keep wires to a minimum.How hard would it be to modify the DIN module to accept 256 inputs? Or is it not feasible due to some technical reason (interference, cable length, speed, ...)? Quote Link to comment Share on other sites More sharing options...
bugfight Posted September 2, 2008 Report Share Posted September 2, 2008 well, i'm no expert at this stuff, but i think the only practical way is to roll your own srio.an example of this is the fast scan matrix example on uCApps.you could modify mios, but that way leads to madness...(however, looking at the src is always informative) Quote Link to comment Share on other sites More sharing options...
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