View Full Version : Stamp Works Experiment #23b: Expanding Outputs Help

03-06-2010, 04:58 PM
I have ten 7 segment displays that I am multiplexing. I am using two 74hc595 shift registers daisy chained together to drive the Anodes.

I am using the demo code provided in Experiment 23b of the Stamp works

When I cycle through the anodes the first eight turn on and off sequentially no problem, the two displays connected to the second shift register however are flashing on and off while the digits on the first register are cycling, this causes a ghosted image on the two displays connected to the second register. I need the displays on the first register to turn off when the displays on the second shift register are cycling.

http://www.youtube.com/watch?v=A88nIHwxOXk The digits start from the left and move 8 places, only one display is lit at a time. When it gets to digit 9 and digit 10 on the far right the digits on register 1 are still lit, I need these off until the two on the end are finished cycling.

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03-07-2010, 12:58 AM

You can set the pattern to WORD and set the Shiftout command for 16 bits, (but still testing for the 10th bit). Get rid of the Counter, also. It was doing what it was supposed to do, counting up in binary on the second S/R.


03-09-2010, 12:34 AM
Did this help?

03-09-2010, 04:27 AM
Could you post your schmatic with the pin connections I would like to use a 74hc595 but Im not sure how to connect it.


03-09-2010, 04:30 AM
Never mind I found it