Help
TK, anybody
The output pin on DOUT is connected through a diode and key contact to the input pin on the
DIN. What value pull up resistor should be on the DIN PIN?
Is a pull up resistor needed on the Dout output pin?
Will the voltage drop to ground on the DOUT pin be lower if a ULN2803 driver chip is used at 5vdc inbetween the shift register and the output pin similar to the setup for driving magnets?
Thanks,
johnc
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Interfacing DOUT w/DIN in a switch matrix
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Posted 25 June 2011 - 17:32
#2
- MIDIbox Newbie
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Posted 22 July 2011 - 19:49
Heres SomeBody,
my Button Matrix without LED has to be connected over common Cathode at DOUTX4.
16x32 - 16 (Col) Channels at 2 Shift Register on DOUTX4 with original Resistors (220) over a Diode [Cathode - Anode] thru 32 Buttons at 4 Shift Register on DINX4 with original Resistors (10k).
I don´t know anything about the setup with ULN2803.
my Button Matrix without LED has to be connected over common Cathode at DOUTX4.
16x32 - 16 (Col) Channels at 2 Shift Register on DOUTX4 with original Resistors (220) over a Diode [Cathode - Anode] thru 32 Buttons at 4 Shift Register on DINX4 with original Resistors (10k).
I don´t know anything about the setup with ULN2803.
This post has been edited by CSC: 05 August 2011 - 22:59
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