I love the old 'scope! You will definitely have to buffer the outputs of the BeagleBone, most of which are only rated for a few mA of drive current. If adding an 'HCT245 style buffer (or something similar) doesn't help and you really need to generate a 10 KHz PWM output signal, you won't be able to do it reliably with the ARM. You should either use one of the hardware PWM outputs, or you can get the PRU to output a PWM signal that fast.
To use the PRU, either setup a new PWM timebase with pwm_period=100000 or just run a stepgen in velocity mode and control the duty cycle with the steplen and/or stepspace settings. ...but neither solution will help with safety if the ARM core crashes and stops running code. Both the hardware PWM and PRU would keep generating the chargepump output and your drivers would remain enabled. On 2/1/2017 12:46 PM, Tom M wrote: > Thank for the quick response. > When we connected charge pump we got a nice 500 Hz signal albeit 3 volts. > When I attempted to create a 10k thread this is what we got as far as a > trace. > > On Feb 1, 2017 9:43 AM, "Kirk Wallace" <[email protected]> wrote: > >> On 02/01/2017 07:02 AM, Kirk Wallace wrote: >> >> ... snip >> >> >>> I seem to recall that the scope traces that got above 3Volts worked. >>> Such as the motherboard port set to EPP worked: >>> http://wallacecompany.com/machine_shop/G540/g540_mb_epp.jpg >>> >>> But set to SPP didn't: >>> http://wallacecompany.com/machine_shop/G540/g540_mb_epp.jpg >>> >> >> ... snip >> >> Oops, bad link above, this should be better: >> http://wallacecompany.com/machine_shop/G540/g540_mb_spp.jpg >> >> >> -- >> Kirk Wallace >> http://www.wallacecompany.com/machine_shop/ >> http://www.wallacecompany.com/E45/ >> >> -- >> website: http://www.machinekit.io blog: http://blog.machinekit.io github: >> https://github.com/machinekit >> --- You received this message because you are subscribed to a topic in the >> Google Groups "Machinekit" group. >> To unsubscribe from this topic, visit https://groups.google.com/d/to >> pic/machinekit/Mv7X6ddtPD4/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected]. >> Visit this group at https://groups.google.com/group/machinekit. >> For more options, visit https://groups.google.com/d/optout. >> > -- Charles Steinkuehler [email protected] -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout.
