User's Manual

Decoder for Atlas N Scale H15/16-44 Locomotives 13
Atlas Model Railroad Co., Inc.
Converting Binary Values of Individual Bits within
a Configuration Variable into the Equivalent
Decimal Value of the Entire CV
Reasons for Setting and Clearing the Individual Bits of a
Configuration Variable
To make a DCC decoder perform in the manner that you wish, you
sometimes need to set or clear individual bits of a CV. To program a
DCC decoder using a DCC system that allows only the writing of
decimal values into CVs (such as the Atlas Master Commander), it is
first necessary to convert the values of all the individual bits of that CV
that are to be set to the binary value 1 into their equivalent decimal
values. It is then necessary to add together all of these equivalent
decimal values.
Procedure for Converting Individual CV Bit Values into a
Decimal Equivalent Value for the CV
The following table illustrates how to calculate the decimal value that
must be written into a CV to set and/or clear a specified set of
individual bits within that CV.
Bit
Number
Decimal
Equivalent
Decimal
Values for
CV
Calculation
0 1
1 2
2 4
3 8
4 16
5 32
6 64
Each bit of a CV that is to be set to the
binary value “1” can be represented by the
equivalent decimal number shown in the
second column of this table. To determine
the equivalent decimal value to be written
into the CV, first write in column 3 of this
table the decimal equivalent values of all
the bits of the CV that are to be set to a
binary 1. Write nothing in column 3 for
each bit of the CV that is to be cleared,
i.e., set to a binary 0. Then add up all the
numbers that you have written in column
3. The sum that you get is the equivalent
decimal value you need to write into the
CV.
7 128
SUM: