I recently purchased 4 seven segment displays from sure electronics. They came with their own shift register board which combines the 74HC595 IC with the ULN2003. I want to be able to tie into this board using the Arduino and after several hours of research and trial and error I have had no luck. The data sheet for the seven segment displays and the shift register board can be found here: http://www.sure-electronics.net/mcu,display/DE-DP005.pdf . I can't even figure out the functions or names of the pins on the shift register board at this point. Any help would be much appreciated.

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    \$\begingroup\$ It might be useful to at least add into your question what you have tried and failed at, as part of the "several hours of research and trial and error". This will help other members understand what level of answer would at all be relevant to you, thus helping formulate more useful answers. \$\endgroup\$ May 21, 2013 at 19:52

1 Answer 1


The names of the pins are clearly labeled on both the back of the board, and the datasheet. enter image description here

PWR_IN is 5v to 15v, 12v preferred. The two regulators on the board provide the appropriate voltages from there.

DIMM IN is the '595's OE, Output Enable Pin
CLK IN is '595's SH_CP AND ST_CP Clock Pins
DATA IN is the '595's SI Serial Input Pin

CLK IN and DIMM IN are buffered to the output side with a buffer chip.
DATA OUT is the '595's Q7", Serial Output Pin, which goes to the next display.
And PWR_IN is directly tied to PWR_Out.

Since Latch and Clock are tied together, a quick search online indicates: I had to add one more clock up/dw because, as the datasheet says, latch clock is one step behind the shift clock, when tied together as a fix to any issues.

Other than that, this can be driven with the regular Arduino ShiftOut library.

The DIMM IN pin must be driven low/0 for the display to be on.

  • \$\begingroup\$ I'm not totally sure what you mean by adding another clock up/dw and would I also set the latch and clock pin to the same pin on the arduino or do I eliminate one of them all together? \$\endgroup\$ May 21, 2013 at 21:18
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    \$\begingroup\$ Don't worry about the latch pin. All you need to do is toggle the clock pin manually. digitalwrite(clock,high) then low, or similar. \$\endgroup\$
    – Passerby
    May 21, 2013 at 21:54
  • \$\begingroup\$ can you give me an example. where would i need to toggle it in the code? \$\endgroup\$ May 24, 2013 at 3:53
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    \$\begingroup\$ Send the data with shiftout(etc); then digitalwrite(pin,high); digitalwrite(pin,low); It might be the other way around, low then high. @user1328147 \$\endgroup\$
    – Passerby
    May 24, 2013 at 11:21

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