SoundTraxx DSD-150/DSX Technical Reference - Manual (Page 19)

Address Mode Direct Mode
Register Mode Ops Mode Short Form
Paged Mode Ops Mode Long Form
Digital Sound Decoder Technical Reference 19
CV 25
SPEED TABLE
SELECT REGISTER
Description
Used to select one of 15 Speed Curves:
bit 7 bit 0
0 USER TBL3 TBL2 TBL1 TBL0
Bits 3-0: TBL3:TBL0, Preset Speed Curves Select Bits
0000
= Speed Curves not used
0001 = Speed Curves not used
0010 = Linear Speed Curve
0011 = Logarithmic Curve 1
0100 = Logarithmic Curve 2
0101 = Logarithmic Curve 3
0110 = Logarithmic Curve 4
0111 = Logarithmic Curve 5
1000 = Logarithmic Curve 6
1001 = Logarithmic Curve 7
1010 = Exponential Curve 1
1011 = Exponential Curve 2
1100 = Exponential Curve 3
1101 = Exponential Curve 4
1110 = Exponential Curve 5
1111 = Exponential Curve 6
Bit 4: USER, User Loadable Speed Table Select
0
= Enable Speed curve defined by TBL3:TBL0
1 = Enable Speed curve defined by CVs 67-94.
Bits 5-6: Not Used. These bits are ignored.
Bit 7: Mid Range Speed Step
This bit is not implemented and always reads as 0.
CV 25 may be programmed with any value between 0 and 31 (0x1F). Values between 02 and 15
(0x0F) allow the user to select from one of 14 predefined speed curves as depicted below. The
logarithmic curves provide a shallower speed response as the throttle is increased. These curves
are useful for locomotives that require a high starting voltage to get moving or matching a highly
geared locomotive to one that has less gearing. The exponential curves are useful for slowing
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