Labview binary to ascii
Similar to the unsigned algorithm, we can use the basis to convert a decimal number into signed binary. We will work through the algorithm with the example of converting to 8-bit binary. We with the largest basis element in this case and decide do we need to include it to make Yes without , we would be unable to add the other basis elements together to get any negative result , so we set bit 7 and subtract the basis element from our value.
Our new value is minus , which is We do not need 64 to generate our 28, so bit6 is zero. We do not need 32 to generate our 28, so bit5 is zero. Continuing along, we need basis elements 8 and 4 but not 2 1, so bits are First we do a logic complement flip all bits to get Then add one to the result to get A third way to convert negative numbers into binary is to first subtract the number from , then convert the unsigned result to binary using the unsigned method. For example, to find , we subtract minus to get Then we convert to binary resulting in This method works because in 8 bit binary math adding to number does not change the value.
We define a signed 8-bit number using the char format. When a number is stored into a char it is converted to 8-bit signed value. A halfword or double byte contains 16 bits. A word contains 32 bits. If a word is used to represent an unsigned number, then the value of the number is. There are 65, different unsigned bit numbers. The smallest unsigned bit number is 0 and the largest is We define an unsigned bit number using the unsigned short format. When a number is stored into an unsigned short it is converted to bit unsigned value.
There are also 65, different signed bit numbers. The smallest signed bit number is and the largest is To improve the quality of our software, we should always specify the precision of our data when defining or accessing the data.
We define a signed bit number using the short format. When a number is stored into a short it is converted to bit signed value. When we store bit data into memory it requires two bytes. Since the memory systems on most computers are byte addressable a unique address for each byte , there are two possible ways to store in memory the two bytes that constitute the bit data. Freescale microcomputers implement the big endian approach that stores the most significant part first. The ARM Cortex M processors implement the little endian approach that stores the least significant part first.
Some ARM processors are biendian , because they can be configured to efficiently handle both big and little endian. For example, assume we wish to store the 16 bit number 0x03E8 at locations 0x50,0x51, then. We also can use either the big or little endian approach when storing bit numbers into memory that is byte 8-bit addressable.
If we wish to store the bit number 0x at locations 0xx53 then. In the above two examples we normally would not pick out individual bytes e. On the other hand, if each byte in a multiple byte data structure is individually addressable, then both the big and little endian schemes store the data in first to last sequence. The Lilliputians considered the big endians as inferiors. The big endians fought a long and senseless war with the Lilliputians who insisted it was only proper to break an egg on the little end.
A boolean number is has two states. The two values could represent the logical true or false. The positive logic representation defines true as a 1 or high, and false as a 0 or low. If you were controlling a motor, light, heater or air conditioner the boolean could mean on or off. In communication systems, we represent the information as a sequence of booleans: For black or white graphic displays we use booleans to specify the state of each pixel. The most efficient storage of booleans on a computer is to map each boolean into one memory bit.
In this way, we could pack 8 booleans into each byte. If we have just one boolean to store in memory, out of convenience we allocate an entire byte or word for it. Most C compilers including Keil uVision define:. Decimal numbers are written as a sequence of decimal digits 0 through 9. The number may be preceded by a plus or minus sign or followed by a L or U.
Lower case l or u could also be used. The minus sign gives the number a negative value, otherwise it is positive. The plus sign is optional for positive values. Unsigned bit numbers between and should be followed by U. You can place a L at the end of the number to signify it to be a bit signed number. The range of a decimal number depends on the data type as shown in the following table.
On the Keil uVision compiler, the char data type may be signed or unsigned depending on a compiler option. Because the ARM Cortex microcomputers are most efficient for 32 bit-data and not bit data , the unsigned int and int data types are 32 bits.
On the other hand, on a 9Sbased machine, the unsigned int and int data types are 16 bits. In order to make your software more compatible with other machines, it is preferable to use the short type when needing bit data and the long type for bit data. Since the Cortex M microcomputers do not have direct support of bit numbers, the use of long long data types should be minimized. On the other hand, a careful observation of the code generated yields the fact that these compilers are more efficient with bit numbers than with 8-bit or bit numbers.
The manner in which decimal literals are treated depends on the context. If a sequence of digits begins with a leading 0 zero it is interpreted as an octal value. There are only eight octal digits, 0 through 7. As with decimal numbers, octal numbers are converted to their binary equivalent in 8-bit or bit words. The range of an octal number depends on the data type as shown in the following table.
Notice that the octal values 0 through 07 are equivalent to the decimal values 0 through 7. One of the advantages of this format is that it is very easy to convert back and forth between octal and binary. The hexadecimal number system uses base 16 as opposed to our regular decimal number system that uses base Like the octal format, the hexadecimal format is also a convenient mechanism for us humans to represent binary information, because it is extremely simple for us to convert back and forth between binary and hexadecimal.
A nibble is defined as 4 binary bits. Each value of the 4-bit nibble is mapped into a unique hex digit. Computer programming environments use a wide variety of symbolic notations to specify the numbers in various bases. The following table illustrates various formats for numbers. If a sequence of digits begins with 0x or 0X then it is taken as a hexadecimal value. In this case the word digits refers to hexadecimal digits 0 through F.
As with decimal numbers, hexadecimal numbers are converted to their binary equivalent in 8-bit bytes orbit words. The range of a hexadecimal number depends on the data type as shown in the following table. Character literals consist of one or two characters surrounded by apostrophes. Otherwise, this information also is converted. Development Course Manual for more information about type casting. For example, consider a GPIB oscilloscope that transfers waveform data in binary notation. The waveform is composed of 1, data points.
Each data point is a 2-byte signed integer. Therefore, the entire waveform is composed of 2, bytes. In [link] , the waveform has a 4-byte header DATA and a 2-byte trailer--a carriage return followed by a linefeed. The block diagram in [link] shows how you can use the Type Cast function to cast the binary waveform string into an array of bit integers. Remember, the GPIB is an 8-bit bus. It can transfer only one byte at a time.