Serial Connection is SLOW

[ejwenger]

Well, I have successfully constructect the serial cable with one problem. The framerate of FMS is approximately 30 when the transmitter is OFF, however, once ON, the framerate drops to 5!

I have changed the serial baud rate in the Windows properties to the highest setting, but no change. Any suggestions?

By the way, the serial schematic found in the FMS help file works perfectly. It solved all of my parallel port problems, and will be the perfect solution once I figure out the slow framerate problem.

[Deimos]

Hi ejwenger,

Looking at the circuit diagram for the FMS Serial Interface, the PPM output of your transmitter gets into your PC via the RI (Ring Indicator) line. Changes on this line cause Interrupts on your PC, which is how FMS determines your controller's settings.

Changing the baud rate on your Serial Port should have no effect on FMS's framerate since the baud rate only applies to the TD (Transmit Data) and RD (Receive Data) lines.

It is possible, I suppose, that your transmitter is only outputting sets of "PPM trains" (for want of a better term) at the rate of only 5 per second, (which does seem kinda slow) and this could be what is slowing down FMS. Perhaps the authors could verify this?

Out of curiousity... have you tried your transmitter on a parallel port?

Anthony.