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Old 06-09-2015, 05:20 AM   #52 (permalink)
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Originally Posted by Theitguy View Post
in your video you had 2 segment led displays running, do you happen to have a schematic drawn up for that?
Or quite simply how did you connect the diver into the arduino? is is through the I2C connector shown on your previous schematic?
Yes. The 4 wires are 5V, Gnd, SDA and SCL.
The SAA1064 is about as simple as it gets without turning into a huge chip package: Power and I2C inputs, 16 constant-current segment drive outputs. That lets you drive two 7+1 segment digits, a bar graph or whatever. It also has a pair of multiplex outputs that let the chip drive twice the LEDs by alternating which pair of digits are lit - two digits share a set of drive outputs, but the multiplex output controls which digit is lit at any given moment. Alternating digits fast enough makes the on/off cycles blend together until they're virtually invisible to the human eye. The switching is done continuously and transparently by the SAA1064 - you just set the mode and feed it data for the second set of digit(s).
Here's a how-to I just stumbled across: Tutorial: Arduino and the NXP SAA1064 4-digit LED display driver
I'm sure mine could be made much more compact by using the surface-mount version and etching an application-specific PCB.
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