Using PORT() for data

Question

This is probably a very easy question for someone out there but It has me stumped. I have a three digit number like 123 or 286 etc. I am sending it from a Mega to NRF24l01+. This is working fine.

I am receiving the number fine with another NRF24l01+ and a Nano. now the problem. I have a 3 digit, 7 segment display. It is also working fine when using this code for a test..

[code]

/*Select a seven segment digit () in sequence.

* load a value into display for testing

*/

int i ;

byte j = B0000 ; //the digit value (0 to 9)

void setup()

{

DDRC = DDRC | B00111111; // set PORT C (digital 5~0) to outputs

pinMode(6, OUTPUT); // digit select pins (Latch signal)

pinMode(7, OUTPUT);

pinMode(8, OUTPUT);

Serial.begin(9600);

}

void loop() {

for (i = 6; i <9 ; i++) //digit select latch

{

digitalWrite(i, HIGH); // open latch

delay(100);

for (j = 0; j <10 ; j++) // test values for the display

{

PORTC = j; // write HEX value to digit

// Serial.print( PORTD ) ; // just for testing

// Serial.print( PORTC ) ; // just for testing

delay(100); //

}

delay(500); // wait a bit to read digit

digitalWrite(i, LOW); // close latch

delay(1000);

Serial.println( byte(i)) ; //only for testing

}

if(i == 9, i=6); //reset digit counter and do it again

}

[/code]

when I run the above code each digit counts up the latches then the next digit counts up. At he end.all is reset and repeats.

My problem is I can't isolate each of the received digits to individually load them into the display. Is there a way to separate the received number into digits so I can load the port? I hope this makes sense.

I can supply the schematic, video, etc. if it would help.

Bill

clem57 · Accepted Answer

I think you need this Adafruit customer service forums • View topic - How to convert a string to a number . It can take 1 cgar at a time and convert to a number. Clem

BigG · Answer

you could avoid string to digit conversion by creating a data structure for each digit for example.

You would declare as follows in Arduino:

struct SEGDISPL { byte dgit1 = 0; byte dgit2 = 0; byte dgit3 = 0; };

SEGDISPL mySegDigits;

// Then assign your 3 digits values of choice

mySegDigits.dgit1 = 2;

mySegDigits.dgit2 = 6;

mySegDigits.dgit3 = 8;

Then use the Serial write function instead of print function to send data via nRF24L01 e.g. Serial.write(&mySegDigits, sizeof(mySegDigits));

This prevents the data from being seen as characters. See: https://www.arduino.cc/en/Serial/Write

Use same data structure on receiver side when reading data from nRF24L01 etc.

You now have your separate digits to display on segment display.

SIMPLER OPTION:

Now as your 3 digits are of the same type (my example is really suited for cases when data is of different type), a simpler method is to just create a byte array rather than use data structure.

E.g. You declare in Arduino

byte mySegDigits[] = {0,0,0};

Then to assign mySegDigits[0] = 2; etc.

Serial.write(&mySegDigits, sizeof(mySegDigits));

etc.

billpenner · Answer

Good info but I think the separation will be done better at the receiving end. It will be better for me to just send a single number then decode it intp digits at the receiver. Thanks for the information.

clem57 · Answer

Below each post is : Like Show 0 Likes (0) • Helpful Yes | No • Comment • Report Actions Click on Yes if helpful. Clem

clem57 · Answer

4K may because of the many function calls you have. Try to simplify the calls to only one serial.print/println without the strings. atoi is a scii to integer function, It takes one or more character strings null terminated and converts to a working integer to do math with like add etc, Your trick here is to play and determine what the shortest code you can generate, Functions tend to be generic so if you do by hand thibgs get better. But that is more work for you Clem