DCC Bit Value Decoder
Example Value (bit 7 -> bit 0) 11011001
Bit
(Decimal
Value)
7(128) 6(64) 5(32) 4(16)
3(8)
2(4)
1(2)
0(1)
Binary
Example
1(on) 1(on) 0(off) 1(on) 1(on) 0(off) 0(off) 1(on)
Decimal
Value
128
64
0
16
8
0
0
1
So, in the above example you simply add up the values in the “Decimal Value” row –
128+64+0+16+8 +0+0+1 = 217. You would write 217 to the CV you were altering.
The above applies to any CV. Also, if you have a CV that already has a value assigned
that you do not want to alter but need to make additions to it, for example CV29, you
would simply add the additional bits you enabled to the existing value to obtain the new
CV value.
For example, if you had a consist address (CV19) set to 5 and you wanted to alter this
to show an engine reversed in the consist you would need to set bit 7 (decimal value =
128) for the engine you want to reverse. To do this - take 128 (the new bit you want to
set) + 5 (the existing bit that you do not want to alter) = 133. You would then write a
value of 133 to CV19.
Premier Bavarian Class 3/6 Express Steam Locomotive
37
NOTE
– An alternative to writing on a Programming Track is to simply Program on
the Main (PoM). MTH engines support PoM to write any CV on the main. However,
read back is not supported on the main. Check with your DCC system's manufacturer
to see about any limitations they may have to PoM.
