Computer Interfacing

Computer interfacing

other symbols on a keyboard have a unique code, which

is usually specified in hexadecimal format. In addition

to keyboard symbols, various control functions, such as

carriage return, line feed — to quote two obvious ones

— are similarly encoded. These hexadecimal values range

from 00

H

to 7F

H

, those from 00

H

to 31

H

being the control

values, the remainder being the true keyboard charac-

ters.

This code is basically a 7-bit code (thus allowing

for 128 different characters to be encoded) with the

eighth bit being used for parity. It is interesting to note

that bits 6 and 7 of the code define the nature of the

ASCII character ...