Go Down

Topic: Reading a byte from the digital pins (Read 626 times) previous topic - next topic


Hello everybody,
I am new user of Arduino and I am learning the difference between the old microprocessor 8080 I have used many years ago and this new PIC. In my brain I remember a simple instruction which loads in the ALU (or in the RAM) one byte from the input port and then you can assign this byte as variable. In Arduino I have not found similar instruction, instead it uses a string, sent by serial line. Where is the trick by loading a parallel byte from input digital pins in the ALU?
Thanks in advance, Godifredo


I don't think we do that anymore.  It's all serial these days.


There's a couple ways you can do this.  If you hook up the lines such that all the IO pins you want are on a single 8-bit port, copying the values in PIN[letter] will grab the inputs.  However, the Arduino isn't laid out to make such port manipulation easy.  As such, you probably would want something like this:

Code: [Select]

uint8_t pins[8] = {/* pin numbers */};

// ...

// read in as byte:

byte reading;
for (uint8_t i = 0; i < 8; i++) {
  reading |= digitalRead(pins[i]) << i;

Of course, this is of rather limited utility - it's usually more useful to just read the relevant pins directly.

Go Up

Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

via Egeo 16
Torino, 10131