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Topic: Shift Registers (Read 1 time) previous topic - next topic

dhenry

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This thread seems to suggest that is not true, but I could be completely wrong?


You are not wrong. People saying "no" in that thread are wrong.

Not only it can be used as input, in some cases, the same pin can be used as input and output at the same time.

And it is a pretty old idea for embedded programmers.

Grumpy_Mike


Quote
This thread seems to suggest that is not true, but I could be completely wrong?


You are not wrong. People saying "no" in that thread are wrong.

Not only it can be used as input, in some cases, the same pin can be used as input and output at the same time.

And it is a pretty old idea for embedded programmers.


Stop beating about the bush you old **** and say how you get signals into the arduino from a serial input parallel output shift register.
Otherwise shut up.

dannyn382


dannyn382
In the first post you said:-
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I am using an Arduino Uno,

So this is wrong
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The analog on my board is in only.

It is not. If you address the pins Analog in 0 as pin 14, Analog in 1 as pin 15 and so on these can be used as digital inputs or outputs.


Grumpy Mike and Holmes, I apologize for my misinformed first post. I have done some more research, and it looks if you are indeed correct. I will try this soon and wire it up and see if I have enough pins now.

Strykeroz, I still like your idea of the MCP23008 or MCP23017 chips, and I might try this just to learn something new even if I can solve this particular project with the analog pins.

Thanks for everyone's help and input!

PeterH


It is not. If you address the pins Analog in 0 as pin 14, Analog in 1 as pin 15 and so on these can be used as digital inputs or outputs.


This dual nature of the analog inputs is very handy. I was surprised (but very pleased) to discover yesterday that it's even possible to enable the internal pull-ups while using the pin as an analog input - which was very convenient to reduce the external part count. It makes sense that it works, but it's certainly not something I'd have taken for granted.
I only provide help via the forum - please do not contact me for private consultancy.

arduinoadrian

I just needed to add 3 more lines (Output) so I used a 74HC138 and a 74HC14, I already had in my shop. No need to go get anything else. The thing works just fine. I used the 74HC14 because I already had NPN transistors mounted on the board, but with PNPs I wouldn't need it. It can be used to add 8 (Output) lines at the expense of using 3 to send it the code.
Perseverance is 90% of the solution. The remaining 10% is more perseverance.

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