Page 24 Non-Sound Decoder MX618 - MX634 and Sound Decoder MX640 - MX648
3.14 The NMRA-DCC function mapping
ZIMO small-scale decoders have between 4 and 12 function outputs (FO). Things connected to these
outputs (lights, smoke generator etc.) are switched ON and OFF with the function keys of the cab.
Which function key controls which function output can be
defined with the NMRA’s function mapping
CV‘s #33 to #46.
Unfortunately, this function mapping also has its limitations (only one 8-Bit register is available for
each function, which leaves only 8 outputs to select from) and only the headlight function is intended
to change with direction.
F
un
c
tion
k
e
y
on
the
c
ab
CV
Number key
on ZIMO
cabs
Function outputs
Function outputs
FA12 FA11 FA10
FA9
FA8
FA7
FA6
FA5
FA4
FA3
FA2
FA1
Rear
light
Front
light
F0
#33 1 (L) fw
7
6
5
4
3
2
1
0
F0
#34 1 (L) re
7
6
5
4
3
2
1
0
F1
#35
2
7
6
5
4
3
2
1
0
F2
#36
3
7
6
5
4
3
2
1
0
F3
#37
4
7
6
5
4
3
2
1
0
F4
#38
5
7
6
5
4
3
1
0
F5
#39
6
7
6
5
4
3
2
1
0
F6
#40
7
7
6
5
4
3
2
1
0
F7
#41
8
7
6
5
4
3
2
1
0
F8
#42
9
7
6
5
4
3
2
1
0
F9
#43
0
7
6
5
4
3
2
1
0
F10
#44
1
7
6
5
4
3
2
1
0
F11
#45
2
7
6
5
4
3
2
1
0
F12
#46
3
7
6
5
4
3
2
1
0
The black dots in the table above indicate the default settings at the time of delivery, where each func-
tion key corresponds to the same numbered function output. Therefore, the following values were writ-
ten to
these CV’s by default:
CV #33 = 1
CV #34 = 2
CV #35 = 4
CV #36 = 8
CV #37 = 2
CV #38 = 4
CV #39 = 8
CV #40 = 16
CV # 41 = 4
and so on..
EXAMPLE of a function mapping modification: The F2 key (ZIMO #3 key) should switch in addition to
output FO2 also output FO4. Moreover, F3 and F4 should NOT switch FO3 and FO4 but rather FO7
and FO8 (this could be couplers, for example). New values are to be entered into the relevant config-
uration variables as follows:
CV #36=40
CV #37 = 32
CV #38 = 64
F2
3
#36
7
6
5
4
3
2
1
0
F3
4
#37
7
6
5
4
3
2
1
0
F4
5
# 38
7
6
5
4
3
2
1
0
3.15 The extended ZIMO function mapping
(not for MX621)
Since the original NMRA function mapping does not allow for some desirable configurations some ex-
tensions are offered by ZIMO decoders, which are described on the following pages. Most of these
options are related to the ZIMO special
CV #61.
Note: Some of the CV #61 variations (1, 2, 3…) have been replaced over the years by other more
practical applications.
Programming
CV #61 = 97
offers an
Alternative
“function mapping” without “left shift”:
CV #61 = 97 abolishes the left shift of higher CV’s (#37 and up, according to the original NMRA func-
tion mapping), which allows higher function keys to be mapped with lower function outputs (i.e. Func-
tion output 1 (FO1) cannot be mapped with function key F4 using the NMRA function mapping, but is
possible with the ZIMO extended mapping).
FO6 FO5 FO4 FO3 FO2 FO1 Headlight
rear front
F0
1 (L) for.
#33
7
6
5
7
6
5
7
6
5
7
6
5
4
3
2
7
6
5
4
3
2
7
7
6
5
4
3
2
1 0
F0
1 (L) rev.
#34
7
6
5
4
3
2
1
0
F1
2
#35
7
6
5
4
3
2
1
0
F2
3
#36
7
6
5
4 3
2
1
0
F3
4
#37
7
6
5 4
3
7
6
5
2
1
0
F4
5
#38
7
6 5
4
3
2
1
0
F5
6
#39
7 6
5
4
3
2
1
0
F6
7
#40
7
6
5
4
3
2
1
0
F7
8
#41
7
6
5
4
3
2
1
0
F8
9
#42
7
6
5
4
3
2
1
0
NOTE:
The earlier options CV #61 = 1, 2, 11…15 as well as CV #61 = 98 were discontin-
ued with SW-
Version 34 and replaced with the “Swiss Mapping“ (see next chapter).
