The pin should be 3.3V if it is connected correctly inside the processor.. Is it connected to anything externally?
Gerald On Mon, Jun 30, 2014 at 7:16 PM, <[email protected]> wrote: > So, I have one of the PRU's toggling a GPIO output to create a ~50MHz > clock. On the 'scope I can see the voltage of the signal is ~0.8v not 3.3 > when it's running more slowly. > > This is toggling pin P8:11 (GPIO1_13) by the way, and I'm not sure if > there's any L/C on-board that is slowing it down. I've set up /lib/firmware/ > BB-BONE-PRU-00A0.dts to look like: > > /* > > * pru dts file BB-BONE-PRU-00A0.dts > > */ > > /dts-v1/; > > /plugin/; > > > > > / { > > compatible = "ti,beaglebone", "ti,beaglebone-black"; > > > > /* identification */ > > part-number = "BB-BONE-PRU"; > > version = "00A0"; > > exclusive-use = > > "P8.13"; > > > > fragment@0 { > > target = <&am33xx_pinmux>; > > __overlay__ { > > mygpio: pinmux_mygpio{ > > pinctrl-single,pins = < > > 0x34 0x0E > > >; > > }; > > }; > > }; > > > > fragment@1 { > > target = <&ocp>; > > __overlay__ { > > test_helper: helper { > > compatible = "bone-pinmux-helper"; > > pinctrl-names = "default"; > > pinctrl-0 = <&mygpio>; > > status = "okay"; > > }; > > }; > > }; > > > > fragment@2{ > > target = <&pruss>; > > __overlay__ { > > status = "okay"; > > }; > > }; > > }; > > > ... where I tried to set the slew-rate to 'fast', disable pull-downs, and > set mode 6 for the pin, thus letting me access the pin as r30:15 > > Is there anything I can do to increase the voltage of the output signal ? > Am I stuck with it ? Or is it an artifact of the pin I happened to choose ? > > Cheers > Simon > > -- > 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 [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
