Dave,
Thanks for the reply. Happy New Year!
First, I'm not using Digitrax, I'm using EasyDCC. I think Digitrax just got into this conversation as an example system. I'm not sure how much that matters. JMRI supports EasyDCC, so that should be no problem, except a different JMRI driver.
I'm not sure how to fit my stuff into your diagram. Here's an attempt, showing where I'm confused, stuck, or just ignorant...
Your example: JMRI <-> FTDI Drivers <-> LocoBuffer-USB <-> LocoNet <-> DS64 <-> Tortoise
My plan: JMRI <-> Drivers/JMRI interface <-> Serial cable <-> Layout control computer <-> Serial cable <-> EasyDCC
????????????????????????????? ? ?????????????????????????????????????????? or network?????? 486-33 with expansion slots
??????????????????????????? ?????????????????????????????????????????????????????????????????????? MD-DOS
?????????????????????????????????????????????????????????????????????????????????????????????????? Compiled BASIC control program
???????????????????????? ? ? ?????????????????????????????????????????????????????????????????????? Assembly language I/O driver
????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ^
????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? v
?????????????????????????????????????????????????????????????????????? ? ????? Railroad interface I/O board <-> Parallel cable <-> Railroad hardware
In the layout control computer, the I/O is passed between the control program and I/O driver by mapping the data in shared RAM tables. The control program puts data in the output RAM area, and inputs data from the input ram area. The interrupt triggered I/O driver sends output data from the shared output RAM to the railroad hardware, and reads input data from the railroad hardware and stores it in the shared input RAM.
If I can connect the computer to JMRI, then the compiled BASIC control program would just pass I/O data between RAM and the JMRI interface.
The PC may be too out of date and not powerful enough to run JAVA and JMRI, so may need to be on a different computer. I can't upgrade it very far, as I need an "IBM AT" expansion slot to hold my Railroad I/O board. All my newer old computers don't have any. JAVA on another computer is acceptable, I could use a newer one for dispatching and to host JMRI.
My original question was about how to identify the data in JMRI so it could be mapped into my I/O RAM. All the turnouts on my JMRI panel are labelled by JMRI as TO1, TO2, TO3, and so on. All the photodetectors are labelled as ISPD00, ISPD01, ISPD02, and so on. Layout Editor added the IS prefix to all my typed in designators when I was adding them to the panel. I don't know how to identify block occupancy, photodetector, and turnout position input data so it displays on my LE panel, or how to get turnout position, reverse loop phase control, and block power control data output from JMRI, and map it into my I/O.
I think Bob Jacobsen's following message may help me there.
Don Weigt
