how to drive RTSI line with 660x?

[fmhess]

The 660x boards are supposed to be about to output signals onto the RTSI bus, but the register-level manual and example code do not appear to give any information on how to configure an RTSI line as an output, or select what signal you want to drive onto the RTSI line. The register-level manual only explains how to select an RTSI line to use as an input signal to a counter. Is there any information available about the relevant RTSI registers for configuring them as outputs?

[Tom_W_[DE]]

Hi Frank-

Which signals are you attempting to output to RTSI?  Do you intend to use them for synchronization or just to "bounce" signals off of for internal routing?  This functionality exists but is indeed undocumented so we'll have to dig a little bit to get the info you need.

Thanks-

[fmhess]

I've got two 6602 boards and I want the counters on both boards to all get the same gate signal (which is being generated externally). So, I'd like to somehow get an external signal onto one of the RTSI lines, then have the rest of the counters use the RTSI line for their gate signal. I know how to make a counter use an RTSI line as its gate signal, but I don't know how to get an external signal onto an RTSI line through a 660x board. For example, if I could tell a 660x board to route the gate input for its counter 0 onto the RTSI bus, that would work fine. I believe I know how to do that with a m-series board for example, but not a 660x. I'm also interested in general in documentation for other signals which can be routed onto RTSI on a 660x, since I could add support for them to the comedi driver if I have documentation. Basically, I want to know about the 660x analogues of the RTSI_Trig_A_Output_Register, RTSI_Trig_B_Output_Register, and RTSI_Trig_Direction_Register registers from the STC chip.

[Ed W]

Hi Frank-

I've created two wrapper functions that will allow you to internally connect and disconnect a counter source or gate line from either of the two TIO chips on the NI-6602's to one of the RTSI lines.  These are attached in the modified 660x example programs. 

Keep in mind that there is no resource management included in these functions.  Any routes that you create will remain connected until they are either explicitly disconnected (using the attached function) or the computer is rebooted.  In addition, using these routing functions, it is possible to double-drive a RTSI line from two source or gate lines, possibly damaging the board.  I would recommend putting a very low limit on the number of routes a user is able to create at a single time, or adding some other form of resource management, before including these capabilities in a "shipping version" of your driver.

That said, I hope these functions help.  Please post back if you have any questions.  Thanks-

Ed W.

Message Edited by Ed W on 07-24-2008 02:56 PM

Message Edited by Ed W on 07-24-2008 02:57 PM

[fmhess]

Thanks a lot for the example code. So I gather from your warnings that writing any new value to a RTSI_ConfigX_X register is not enough to completely undo the effects of the previous write to the same register? You have to specify the same source with the direction bit cleared in order to un-route it and prevent damage? Also, there are no offsets for the TG_X_LevelEdgeReg and TG_X_CombinationReg of counters 4 through 7 on the 6602. Or can only the counters of the first TIO chip be routed onto an RTSI line?