770/771 Čmeliak – 8bit MTB TT Next18

Project version 206.2.1
770/771 Čmeliak – 8bit MTB TT Next18
8bit

Sound sample

Project Information

  • Optimised for the MTB TT model with a Next18 connector.
  • Designed for 8-bit ZIMO MX sound decoders.
  • Recommended minimum decoder software version is 40.22.
  • The factory default address is 3.
  • Program CV8 = 8 to reset the decoder to the project defaults.

Function Assignment

Function mapping and CV settings can be modified.

  • F0 Position white lights
    Affected function output: FA0v, FA0r
    Direction dependent
  • F1 Red lights
    Affected function output: FA1, FA2
    Direction dependent
  • F2 Headlight
    Affected function output: FA4
    Direction dependent, linked to F0 being on
  • F3 Shunting mode - position lights in cross pattern
    Affected function output: FA0v, FA0r
    • speed range reduced to ½
    • reduces acceleration / braking times to ¼ of CV3 and CV4
    • turns off red lights if they are on
    • turns off headlight if it is on
    • triggers short horn at start
  • F4 Short horn
  • F5 Coasting
    Idle running sound regardless of set speed
  • F6 Engine acceleration to max RPM
    Independent of set speed, even when stationary
  • F7 Long horn
  • F8 Sound on/off
    Engine
  • F9 Cab lighting
    Affected function output: FA3
    Turns off when starting
  • F10 Short whistle
  • F11 Long whistle
  • F12 Uncoupling screw down
  • F13 Uncoupling screw up
  • F14 Sanding
  • F15 Dispatcher whistle - new
    Call to readiness
  • F16 Dispatcher whistle - old
    Call to readiness, departure
  • F17 Compressor
  • F18 Switching sound sets
    Loaded / unloaded locomotive, when stationary
  • F19 Wheel squealing in curves
  • F20 Unused
  • F21 Unused
  • F22 Unused
  • F23 Unused
  • F24 Unused
  • F25 Unused
  • F26 Sound muting
  • F27 Volume decrease
  • F28 Volume increase

Setting Maximum Speed

Use CV57 to set the maximum speed. Changing CV5 affects the sound range and throttle curve, while CV57 does not change the CV3/CV4 timings.

Shunting Mode

Shunting mode turns on all four marker lights. Disable it with CV37 = 0 and re-enable with CV37 = 3. The mode also turns off the red lights and headlight; override this behaviour by setting CV430 = 0 and back to CV430 = 3 when required.

The mode halves the speed range and reduces acceleration/braking times to a quarter of the CV3/CV4 values. Disable it via CV124 = 144; complete deactivation of the timings is possible with CV124 = 147. The default setting is CV124 = 146.

The script-driven short horn requires F3, engine sound on via F8, and starting from zero speed. CV837 = 8 disables it (default CV837 = 0).

F5 Coasting vs F6 Engine to Maximum RPM

If both functions are active, coasting (F5) takes precedence.

Cabin Lighting

The cabin light switched by F9 automatically goes off while the model is moving and turns back on when stationary. Disable this script with CV837 = 16 (default CV837 = 0).

For lighting without automatic switching, set CV43 = 16 together with CV837 = 16. Return to the default by programming CV43 = 0 and CV837 = 0.

Compressor

Two script-driven modes:

  1. Random activation while the engine sound (F8) is on; enabling F17 cancels it.
  2. Direct activation via F17 that requires F8 and zero speed.

CV837 = 1 disables F17, CV837 = 2 disables the random mode, and CV837 = 3 disables both.

Curve Squeal

Curve squeal needs F19 and F8 enabled, speed above 14 and below 100 (range 0–126). Set CV837 = 4 to disable the effect.

Custom Function Mapping

Use CV400 – CV428 for custom mapping if needed. The project itself does not rely on these CVs.

Decoder Reset

Program CV8 = 8 whenever you need to restore the default settings.

Basic CV Settings in Project

  • CV3 = 16
  • CV4 = 14
  • CV5 = 1
  • CV6 = 1
  • CV29 = 14
  • CV33 = 1
  • CV34 = 2
  • CV35 = 12
  • CV36 = 32
  • CV37 = 3
  • CV38 = 0
  • CV39 = 0
  • CV40 = 0
  • CV41 = 0
  • CV42 = 0
  • CV43 = 0
  • CV44 = 0
  • CV45 = 0
  • CV46 = 0
  • CV57 = 125
  • CV61 = 97
  • CV105 = 145
  • CV106 = 5
  • CV124 = 146
  • CV125 = 88
  • CV126 = 88
  • CV127 = 90
  • CV128 = 89
  • CV129 = 88
  • CV130 = 88
  • CV190 = 3
  • CV191 = 2
  • CV254 = 206
  • CV255 = 2
  • CV256 = 2
  • CV266 = 100
  • CV395 = 130
  • CV396 = 27
  • CV397 = 28
  • CV430 = 3
  • CV432 = 193
  • CV433 = 196
  • CV434 = 194
  • CV435 = 196
  • CV836 = 0
  • CV837 = 0

Sound Sample Numbers

F4 CV522 40 Short Horn
F7 CV531 39 Long Horn
F10 CV540 37 Short Whistle
F11 CV543 42 Long Whistle
F12 CV546 38 Screw Coupler Down
F13 CV549 43 Screw Coupler Up
F14 CV552 36 Sanding
F15 CV555 44 New Dispatcher Whistle
F16 CV558 45 Old Dispatcher Whistle
script 46 Compressor
script 47 Wheel Squeal in Curves

"Script" means that the corresponding sound is used inside a script outside the normal CV mapping. The number is provided for standalone use when the script is disabled.