I'm trying here is to let the real-time units of the BeagleBone generate the signals for a stepper motor.
In this post: it works! Let's put everything together.
Initialise the Sleep and Reset Signals
The pins P9_11 and P9_13 are used. I'm controlling them from the Linux command line.
|BB MUX||BB P9||Driver function|
To start, set sleep on and reset off
sudo -i # sleep on echo out > /sys/class/gpio/gpio30/direction echo 0 > /sys/class/gpio/gpio30/value # reset off echo out > /sys/class/gpio/gpio31/direction echo 0 > /sys/class/gpio/gpio31/value
Set the PRU MUX signals and Load PRU Firmware
config-pin P9_31 pruout config-pin P9_29 pruout
cp /home/debian/bin/bb_PRU_STEPPER.out /lib/firmware/bb_PRU_STEPPER.out echo 'bb_PRU_STEPPER.out' > /sys/class/remoteproc/remoteproc1/firmware echo 'start' > /sys/class/remoteproc/remoteproc1/state
Initialise the Stepper Motor Driver via SPI
I'm assuming that you installed the SPI overlay as explained in this post and created the binary in this post.
Wake Up the Stepper Motor Driver
# sleep off echo 1 > /sys/class/gpio/gpio30/value
At this point everything is prepared, and you are ready to ....
Tell PRU to Step the Motor
This is it! Let's take 20 steps back and forth:
echo "120" > /dev/rpmsg_pru30 echo "020" > /dev/rpmsg_pru30
Submit as many commands as you want.
Once you disable sleep mode, the motor will pull 600 mA. It's locked in position. It will get hot.
If you don't play with the motor, or your device doesn't need the motor be kept locked in position, put the driver back to sleep:
cd /sys/class/gpio/gpio30 echo 0 > value
Finished? Clean Up.
echo 'stop' > /sys/class/remoteproc/remoteproc1/state
config-pin P9_31 default config-pin P9_29 default