The Microcontroller Idea Book - Jan Axelson's Lakeview Research

Appendix C
This table shows the value of each digit in the decimal number 193:
Decimal digit 1 9 3
Digit multiplier 10 2 10 1 10 0
Digit value 100 90 3
Binary Numbers
In the binary number system, each digit represents a value raised to a power of 2. The
numbers use only two of the ten decimal digits (0 and 1).
Binary representations are useful when you need to quickly see the value of each bit in a
byte. For example, you might want to set, clear, toggle, or read a bit in one of the 8052’s
special function registers (TCON, PCON, and so on). Or, in a control circuit, individual bits
might control switches or relays. BASIC-52’s logical operators offer a way to control and
display individual bit values.
This table shows the value of each digit in 1100 0001, which is the binary representation of
the decimal number 193:
Binary bit 1 1 0 0 0 0 0 1
Bit multiplier 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2 0
Bit value (decimal) 128 64 0 0 0 0 0 1
Hexadecimal Numbers
In the hexadecimal (or hex) number system, each character represents a value raised to a
power of 16. There are 16 characters, with the letters A through F representing the decimal
values 10 through 15.
Because each character in a hex number represents 4 bits, hex numbers are a convenient,
compact way to express 8-bit or 16-bit numbers. In BASIC-52, you enter hex values at the
host system’s keyboard by adding a trailing h to the number. (Example: 1Fh.) If the first
character is in the range A-F, you must also add a leading 0. (Example: 0E9h.) BASIC-52’s
PH0. and PH1. operators display numbers in hex format on the host computer’s screen.
272 The Microcontroller Idea Book