How do I put 16 bit numbers into my code in binary form?

Projects Programming
1

I thought writing B1110111111111111 should have worked but it throws this error

Arduino: 1.8.15 (Windows 10), Board: "Arduino Nano, ATmega328P"

C:\Users\*********\Documents\Arduino\synth\synth.ino: In function 'void loop()':

synth:46:12: error: 'B1111111111111111' was not declared in this scope

       case B1111111111111111:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:46:12: note: suggested alternative: 'B11111111'

       case B1111111111111111:

            ^~~~~~~~~~~~~~~~~

            B11111111

C:\Users\*********\Documents\Arduino\synth\synth.ino:49:7: warning: large integer implicitly truncated to unsigned type [-Woverflow]

       case 1111111111111101:

       ^~~~

synth:53:12: error: 'B1111111111111011' was not declared in this scope

       case B1111111111111011:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:53:12: note: suggested alternative: 'B11111101'

       case B1111111111111011:

            ^~~~~~~~~~~~~~~~~

            B11111101

synth:57:12: error: 'B1111111111110111' was not declared in this scope

       case B1111111111110111:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:57:12: note: suggested alternative: 'B11111101'

       case B1111111111110111:

            ^~~~~~~~~~~~~~~~~

            B11111101

synth:61:12: error: 'B1111111111101111' was not declared in this scope

       case B1111111111101111:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:61:12: note: suggested alternative: 'B11101111'

       case B1111111111101111:

            ^~~~~~~~~~~~~~~~~

            B11101111

synth:65:12: error: 'B1111111111011111' was not declared in this scope

       case B1111111111011111:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:65:12: note: suggested alternative: 'B11101111'

       case B1111111111011111:

            ^~~~~~~~~~~~~~~~~

            B11101111

synth:69:12: error: 'B1111111110111111' was not declared in this scope

       case B1111111110111111:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:69:12: note: suggested alternative: 'B11101111'

       case B1111111110111111:

            ^~~~~~~~~~~~~~~~~

            B11101111

synth:73:12: error: 'B1111111101111111' was not declared in this scope

       case B1111111101111111:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:73:12: note: suggested alternative: 'B01111111'

       case B1111111101111111:

            ^~~~~~~~~~~~~~~~~

            B01111111

synth:77:12: error: 'B1111111011111111' was not declared in this scope

       case B1111111011111111:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:77:12: note: suggested alternative: 'B01111111'

       case B1111111011111111:

            ^~~~~~~~~~~~~~~~~

            B01111111

synth:81:12: error: 'B1111110111111111' was not declared in this scope

       case B1111110111111111:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:81:12: note: suggested alternative: 'B01111111'

       case B1111110111111111:

            ^~~~~~~~~~~~~~~~~

            B01111111

synth:85:12: error: 'B1111101111111111' was not declared in this scope

       case B1111101111111111:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:85:12: note: suggested alternative: 'B01111111'

       case B1111101111111111:

            ^~~~~~~~~~~~~~~~~

            B01111111

synth:89:12: error: 'B1111011111111111' was not declared in this scope

       case B1111011111111111:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:89:12: note: suggested alternative: 'B01111111'

       case B1111011111111111:

            ^~~~~~~~~~~~~~~~~

            B01111111

synth:93:12: error: 'B1110111111111111' was not declared in this scope

       case B1110111111111111:

            ^~~~~~~~~~~~~~~~~

C:\Users\*********\Documents\Arduino\synth\synth.ino:93:12: note: suggested alternative: 'B01111111'

       case B1110111111111111:

            ^~~~~~~~~~~~~~~~~

            B01111111

exit status 1

'B1111111111111111' was not declared in this scope



This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.
2

0b1110111111111111

1 Like
3

thanks

4

The 256 eight bit constants B00000000 through B11111111 are predefined for you by the Arduino IDE.

5

Also, all shorter (7-bit, 6-bit... 1-bit) binary numbers. That's why you can't use a variable name of B0, B1, B00, B01, B10, B11...

Note: Just like the hexadecimal prefix: 0x00/0X00, the 'b' is not case sensitive so you can use 0B1110111111111111 as well as 0b1110111111111111.

6

One of the most useless "helpful" additions of the "Arduino Language". What the heck is wrong with the standard 0bxxxxxxxx format?

It's almost as dumb as:

typedef bool boolean;
1 Like
7

**Just FYI - **
Most programmers will use hexadecimal instead of binary. It's actually easier and less error-prone (especially with 16-bits or more) because you don't have to count the bit-positions.

You can easily learn to convert between hex & binary (of any size) in your head. It's a LOT easier than converting between binary & decimal... Every nybble (4-bit "pattern") converts exactly to a hex value so you only have to learn 16 conversions and you already know 0000 & 0001 and you may already know F hex = 1111 binary.

8

It depends on what the data represents. A bitmap image, for example, can usefully be written in binary—a 1 is black and a 0 is white (or vice versa)—and it's fairly easy to see the image right in the code.

9

Then waht is the difference between the following two styles of declarations/definitions?

byte x = 0b10101010;
byte x = B10101010;
10

The first one works on many compilers. The second one only works in an Arduino sketch (and for .cpp files, only if Arduino.h is included).

1 Like
11

Perhaps ANY complier that conforms to the C++ standard?

12

For C++14 and above.
https://en.cppreference.com/w/cpp/language/integer_literal

For earlier standards it's not included. I'm not sure what C++ standard the Arduino IDE is using.

14

I was reading pins and bitshifting and all that good stuff. Thats why I used binary formating

15

B -- can have no more than 8 bits.
0b -- can have 'any' number of bits

1 Like
16

It wasn't "standard."

JohnWasser says it is standard starting in 2014. Arduino was written in ~2003. I'm not sure that even gcc had binary constants in 2003.

(Hmm. The oldest version I have lying around is 0013, and that's using a compiler from 2008. It does have the binary constant support.)

17

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