Really interesting post!! But I can't seem to find this thread on the new Beaglebone forums webpage over here: https://forum.beagleboard.org/
Am I missing something or just loosing my mind? On Friday, April 16, 2021 at 1:36:16 PM UTC-4 Dennis Bieber wrote: > On Thu, 15 Apr 2021 09:35:20 -0700 (PDT), in > gmane.comp.hardware.beagleboard.user Walter Cromer > <walterc-2dFtBuzUeF/tpnmuczy8b...@public.gmane.org> wrote: > > > >So if I had an application that had a sensor A that needs to be read > every > >10ms and sensor B that only needs to be read every minute, I could wire > >channel 1 to sensor A and assign it to step 1 and wire channel 2 to > sensor > >B and assign it to step 2. > > > >Then at startup, when I want to read both sensors, I enable steps 1 and 2 > >but not 3-16. This saves time on the read as channels 3-7 aren't needed > >and steps 3-16 aren't needed so I don't use them. Then after the initial > >read when I don't need to read sensor B until a minute passes, I can > change > >STEPENABLE so only step 1 is enabled and execute a read every 10 ms. Only > >sensor A would be read. Then at one minute intervals, I change STEPENABLE > >so steps 1 & 2 are enabled and when read is triggered, sensors A and B > are > >read. > > > > Seems like a lot of fiddling around with step enables, and assumes ADC > reading is a one-shot operation. I'd likely just create a process loop with > major frame of 1 minute, minor frame of 10ms (use a "frame counter" that > you increment after every read), and read both sources each time -- but > only report the one-minute source at top of major frame; counter at 60000 > if my calculations are right). > > The ADC configurations supports continuous mode in which, after all > enabled steps are processed, it loops back to the top and restarts the step > sequence. Note: > > " > 12.3.4 One-Shot (Single) or Continuous Mode > > When the sequencer finishes cycling through all the enabled steps, the > user can decide if the sequencer should stop (one-shot), or loop back and > schedule the step again (continuous). > > If one-shot mode is selected, the sequencer will take care of disabling > the step enable bit after the conversion. If continuous mode is selected, > it is the software’s responsibility to turn off the step enable bit. > " > ... if doing one-shot, you don't have to turn off the second step enable... > You have to, instead, turn ON the steps you want active before doing the > reads -- every time. > > Also pertinent -- as soon as any step is enabled, the ADC goes out of > IDLE to handle enabled steps. There is a master Enable in the CTRL register > -- to synchronize the reads, you'd likely have to set it to 0, program the > steps, then set it to 1 to start the ADC. > > > > > -- > Dennis L Bieber > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/4c5b55c6-c1be-4c39-adbe-ff2a6339ffc0n%40googlegroups.com.
