[beagleboard] PRU Development

I'm trying to learn to program the PRU's on the BeagleBone Black to provide a stable and accurate clock pulse in the 10kHz to 800kHz range and I'm having a difficult time finding what is best to learn. I started with the Exploring BeagleBone book by Derek Molloy which is fantastic but with the exa

[beagleboard] PRU Pin Toggle

This is a followup to a past post on the PRU's. I'm looking to provide a clock pulse in the 100kHz range plus send additional pulses out of the PRU and receive a couple other pulses back from a sensor. I've been able to load the device tree overlays for pins P8.11, P8.12, P8.15, P8.16 and P9.24

[beagleboard] Re: PRU Pin Toggle

Good news. The issue appears to be resolved by using a bit shift as in: gpio = 1 << 15;// to toggle P8.11 or gpio = 1 << 14;// to toggle P8.12 Mike On Fri, Apr 28, 2017 at 11:34 AM, M Pitman wrote: > This is a followup to a past post on the PRU's. I'm loo

[beagleboard] PRU pins

I am having a very strange issue trying to send pulses on the the P8_11 and P8_12 pins using pru0. The intent is to create a 100kHz pulse on P8_11 and periodically send a pulse on P8_12. I've tried using bit shifting and straight hex values and get the same results. As you can see in the code, t

[beagleboard] PRU Timing in C

I've encountered a big issue trying to provide accurate timing of pulses sent from pru0. I'm toggling one pin and trying to set another pin low for just a single low cycle of the first pin. This worked fine in assembler language but in C the timing of the second pin based on the first pin being l

[beagleboard] PRU timing with __delay_cycles()

I seem to have discovered an anomaly with the __delay_cycles command trying to get precise timing on the PRU's. Jason asked that I post my results for all to see. My desire was to create a steady clock pulse on P8.11 and then set P8.12 low for just a single low cycle of P8.11. Then P8.12 was to

[beagleboard] Pointers and dereferencing the data

I'm trying to read data collected from an ADC chip on one of the PRU's of the Beaglebone Black and I'm having difficulty interpreting what I'm seeing. Using Derek Molloy's website as a guide, I use the commands unsigned int spiData[3]; spiData[1] = readFileValue(MMAP1_LOC "addr"); to get

[beagleboard] Dereferencing an address in memory

I'm trying to get to the values of data stored in memory on the Beaglebone Black and experiencing a very fundamental problem. I have the following C code running in Linux. int *p; int value; p = (int *)0x4A30;// Start of PRU0 data ram printf("p addr: 0x%x\n", p); value = *p; print

[beagleboard] Connecting two Beaglebone Blacks

I have a need to connect two Beaglebone Blacks together. One will act as a desktop computer that will send commands to the second one. The second Beaglebone will process the command, create a file and send that file back to the first Beaglebone. The two Beaglebones will be in one container and m

[beagleboard] Connection to Android tablet

I am collecting data from an ADC chip and saving the data to a file on the Beaglebone Black. Currently the commands are sent through PuTTY on a PC using ssh and then sftp sends the file back which is manually loaded and displayed in a Qt program. My desire is to be able to send a command to the B