When I connect a fourth display the multiplexer crashes, the rest of the installation still works (other i/p MPx's) I have tried different Mega2560, different MPx and different displays (TM1637). I have tried adding a 4k7 between Vcc and Z sig, I have also tried decoupling the MPx supply with a 10nF. The DIN and CLK still seem to be ok on all four displays when the thing crashes which is odd...but I only have a 25MHz scope so might be missing things..What am I doing wrong?
May 25, 2019 in 7-Segment Displays by

1 Answer

1. You should not add a resistor between output multiplexer Sig (or pin #26) and Vcc (this recommendation is related to the input multiplexers only)
2. You can add pull-down resistors to each TM "CLK" input (especially if you have long or messy wiring).
3. Check you ground bus, follow the recommendations on this page (below).

May 26, 2019 by

  Thank you for sharing your files,  it is appreciated!  However,  I may wait to see how you make out with the new set of boards, also I am interested in Vlad's comment about the slave board for 7segments coming in the next revision.


As have mentioned in other posts you can make any digit size display with Max7219 chip not making any PCBs.

All you need is to buy the $1 convenient LED Matrix MAx7219 module and  just connect  the 7-segment indicators instead of led matrix: http://simvim.com/svc_digout.html  (see the "Matrix LED Output" chapter in the middle of the page)


Also, I recommend to use simple wiring without PCB, like I show on this page for DM13A LED drivers: http://simvim.com/tips_wiring.html

Randy, back to your question about my setup and number of working displays:

Now I have connected 5 TM1637 displays(+ Max)  but I work with my testing, newer firmware, that was not included yet to the SimVIm database.

Now we have included this firmware with updated timings for TM drivers. Download  the  uploaded today SImVim.dat file, replace it in the plugin folder, and re-upload the master firmware to your board from the plugin.

Good luck, hope all your displays will work better.



  Excellent!  Now have all 8 TM1637's working!