Basics of programming, Programming the cvs, What is a cv – SoundTraxx Tsunami Steam Users Guide User Manual
Page 9: Bits and bytes

Tsunami Steam Sound User’s Guide
Page 6
Programming the CVs
What is a CV?
CV stands for Configuration Variable, which is the industry-adopted term
for a decoder’s user-programmable memory locations. CVs allow you to
customize individual decoder properties such as the address, momentum,
throttle response, sound volume and much more. Once a CV has been
programmed, the setting will be permanently remembered even after the
power has been turned off. A CV can be modified as often as necessary by
simply reprogramming it with a new value.
With the large number of CVs available, first inspection of the available
options may cause confusion and little panic! Relax. As you have already
seen the DSD has been shipped with all CVs pre-programmed so you can
begin using your locomotive immediately without having to worry about what
adjustments to make.
The following paragraphs break the sound decoder’s CVs into various
subsystems so it is only necessary to change a few CV’s at a time. As you
become comfortable with it’s operation, move onto a new section and begin
exploring the options and capabilities found there. For more technically
inclined users, detailed information on any CV can be found in the
Tsunami
Technical Reference.
Bits and Bytes
One of the most confusing aspects of programming a CV is figuring out what
all the different bits, bytes and x’s found in the various decoder manuals
mean. The problem is compounded further by differences in each command
station manufacturer’s user interface. For users unfamiliar with such terms, a
short math lesson (ugh!) is in order before proceeding:
Each decoder CV stores a numeric value that can be represented in one of
three forms:
Decimal - This is the form everyone is familiar with and we use in our day-to-
day lives. Numbers are represented as a sequence of digits composed of the
numerals 0,1,2,3,4,5,6,7,8, and 9.
Hexadecimal - Also referred to as simply “hex”, this is a more specialized
number representation that, in addition to 0 through 9, also uses the
characters A-F. It has the advantage that a given decimal number can be
more compactly represented. For example, the decimal number 127 converts
to a simple 7F in hex (one less digit). This allows user interfaces with a
limited number of digits (i.e., the LCD on your cab) to display a wider range of
numbers.
Binary - Binary numbers get their name from the fact they use only two
digits 0 and 1 called ‘bits’ and is the fundamental number system used by all
computers including the ones found inside a digital decoder. Because there
Basics of Programming