On Thu, 2008-11-20 at 13:45 -0800, Peter C. Wallace wrote: > Is it possible your STEP and DIR inputs have optocouplers returned to 5V?. > This is known problem with the 5I20 (or any of our FPGA cards) outputs since > they only swing 0 to 3.3V.
I think this is the problem based upon page 45 of the IMS483 manual, Figures 7.7 and 7.8. > here are a couple of solutions to this depending on how you are connected to > your step motor drivers > > > 1. If 3.3V drive is enough for the inputs, return the anode of the input > Optocouplers to 3.3V instead of 5V (5I20 connector pin 49 jumper option) I don't think 3.3 Volts will be enough because the recommended R_series in Figure 7.7 is 0 ohms for 5 Volts, meaning there is either an existing series resistance inside the drive, or the optocoupler has a 5 Volt TTL input. > 2. If 3.3V drive is not enough or its inconvenient to get 3.3V to the drive, > set the step and direction outputs into OPEN_DRAIN mode so you get a 5V swing Eric, do this, and use the 5 Volts from pin 49 of P4 on the 5i20 as the "opto supply" (P1:4 on the IMS483). Set W3 on the 5i20 board to the 5 Volt position. I think this will make it work with any of your cables. Thanks, Matt ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
