S88 timings generated by ddx causes issues

Moderator: Moderators

S88 timings generated by ddx causes issues

Postby fred_feuer » 13.11.2010, 22:28


it seems to me that I'm running right now into compatibility issues with S88 sensors and the timing on the S88 bus generated by ddx.

I'm using Rocrail with ddx and (are trying to add) S88 sensors connected via lpt. Problem is that I'm not getting proper data from the S88 sensor back. As sensor I'm right now using the implementation from D. Ratschmeier http://www.railway-lauf.de/GBM-16RM.htm.

When I measure the clock cycle generated by ddx I get values arround 90 us (us = 10⁻⁶ seconds). That seems to be pretty fast according to D.Ratschmeier. Has anybody yet had similar problems with the clock speed on S88?

And another question would be is there already a black and white list of S88 sensors that are working with the ddx timings? A similar list like the one of the decoders which work with ddx and which not.


Postby fred_feuer » 14.11.2010, 17:55

Seems always dumb to answer your own question. But I came across the very helpful parameter of the rocrail.ini:

"s88clockscale" clock=166kHz divided by S88CLOCK_SCALE

This is very helpful. By setting it to 50 I could reduce the clock timing on the S88 bus to about 3kHz. This works now fine for me. At least the one test block gives now the correct response.

Return to ddx