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o added (#39)

o added section in describing how to turn on the eQEP and count the output steps
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lromor authored and hzeller committed Jun 20, 2018
1 parent 51db5c7 commit bb338b8aa67271c31591b2e28840e431f448d292
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@@ -156,6 +156,33 @@ be used for laser cutters. TBD.).

<img src="./img/sample-gcode2ps-laser.png" width=500/>

### Generated loops hardware counter using internal eQEP
The AM335x processor provides an Enhanced Quadrature Encoder Pulse (eQEP).
This can be useful to test the correctness of the number of steps and debug possible drifts.
In order to access it via the Linux file system, it's necessary to load the correct device tree overlay at boot.

For example, to enable the eQEP0, it's necessary to add a line inside

and reboot.

After reboot, `/sys/devices/platform/ocp/48300000.epwmss/48300180.eqep/`
should be populated with some files:
driver enabled modalias mode period position power subsystem uevent

For eQEP0 `P9_42` and `P9_27` are respectively eQEP0A and eQEP0B.
In order to test a specific axis, opportunely connect the **direction** output
on `P9_42` and the **step** output on `P9_27`.

Run `echo 0 > /sys/devices/platform/ocp/48300000.epwmss/48300180.eqep/position` to reset
the counter to zero and start some motion.
You will see the value inside the `position` file change accordingly to the number of LOOPS generated from the PRU.

#### For development testing
This tool is used for the visual end2end output creating a HTML page with
images of a set of testing `*.gcode` files:
@@ -313,4 +340,4 @@ of many-hour long jobs. This might be useful to display to the user.


@@ -0,0 +1,119 @@


## Get one of the latest linux Debian images

Download one of the latest debian images provided by the following [**list**]( This installation guide refers to *bone-debian-9.3-iot-armhf-2018-03-05-4gb.img.xz*.

If necessary, check the integrity of the downloaded image by matching its sha256sum hash and the one provided on the website (on a linux terminal,
just run `sha256sum bone-debian-9.3-iot-armhf-2018-03-05-4gb.img.xz`).

## Flash the SD card
**WARNING**: **Be careful when selecting the device to be flashed, as you may end up losing data inside it.**

Connect an empty SD card to your PC and extract and copy the image over your sd card.

Based on the platform this can be done via the following methods:

#### **Linux**
On a terminal, save the SD card device path by inspecting `lsblk`. The SD card should be under a path similar to `/dev/mmcblkN`. Run on the terminal, `xzcat bone-debian-9.3-iot-armhf-2018-03-05-4gb.img.xz | sudo dd of=/dev/mmcblkN`.
Before extracting the SD card remember to run `sync` in order to flush any remaining buffered I/O operation.

#### **Linux / Mac OS / Windows**
Using the graphical tool ****. Select the downloaded image , the target device and then click on **Flash**.

## Boot

1. Connect the beaglebone to your local LAN with DHCP enabled or via USB.
2. Insert the SD card on the beaglebone slot.
3. Turn on the beaglebone.

### Connect via SSH

If you connected the beaglebone via USB, a virtual Ethernet interface should appear on your PC.

#### **Linux / Mac OS**

Open a terminal and run: `ssh debian@beaglebone.local`
the default password is usually `temppwd`.

#### **Windows**

Download the ssh client from
use as hostname `debian@beaglebone.local` and connect using the usual `temppwd` password.

## Prepare the environment

If the following one-liner:
if lsmod | grep "uio_pruss" &> /dev/null ; then echo "The kernel is BeagleG ready"; else echo "uio_pruss module not present"; fi`

will return `The kernel is BeagleG-ready`, it means that you can skip this section, otherwise you will need some additional steps.

Beagleg as it is now, requires a kernel module called `uio_pruss` (see [this](

To enable it, you will need to edit your `/boot/uEnv.txt`
and change:

###pru_rproc (4.4.x-ti kernel)
###pru_uio (4.4.x-ti, 4.14.x-ti & mainline/bone kernel)

uncommenting the line `uboot_overlay_pru=/lib/firmware/AM335X-PRU-UIO-00A0.dtbo`.

Before rebooting, you will also need to have an updated version of your kernel as you may suffer a bug that will not correctly load the uio_pruss module and device tree overlay.

To do so, run `sudo apt-get update; sudo apt-get upgrade` and on completion,
execute a reboot.

## Install BeagleG

Let's start from fetching the BeagleG repository with:

git clone --recursive

change directory into the repository and run `make`.


## Empty am335x_pru_package folder

When compiling, you might encounter the following error:
make -e -C src all
make[1]: Entering directory '/home/debian/beagleg/src'
g++ -std=c++11 -Wall -I. -I../am335x_pru_package/pru_sw/app_loader/include -I../hardware/BUMPS -D_XOPEN_SOURCE=500 -mtune=cortex-a8 -march=armv7-a -O3 -DCAPE_NAME='"BUMPS"' -DBEAGLEG_VERSION='"2018-06-16 (commit=51db5c7)"' -c -o machine-control.o
g++ -std=c++11 -Wall -I. -I../am335x_pru_package/pru_sw/app_loader/include -I../hardware/BUMPS -D_XOPEN_SOURCE=500 -mtune=cortex-a8 -march=armv7-a -O3 -DCAPE_NAME='"BUMPS"' -DBEAGLEG_VERSION='"2018-06-16 (commit=51db5c7)"' -c -o motor-operations.o
g++ -std=c++11 -Wall -I. -I../am335x_pru_package/pru_sw/app_loader/include -I../hardware/BUMPS -D_XOPEN_SOURCE=500 -mtune=cortex-a8 -march=armv7-a -O3 -DCAPE_NAME='"BUMPS"' -DBEAGLEG_VERSION='"2018-06-16 (commit=51db5c7)"' -c -o sim-firmware.o
g++ -std=c++11 -Wall -I. -I../am335x_pru_package/pru_sw/app_loader/include -I../hardware/BUMPS -D_XOPEN_SOURCE=500 -mtune=cortex-a8 -march=armv7-a -O3 -DCAPE_NAME='"BUMPS"' -DBEAGLEG_VERSION='"2018-06-16 (commit=51db5c7)"' -c -o pru-motion-queue.o
make -C ../am335x_pru_package
make[2]: Entering directory '/home/debian/beagleg/am335x_pru_package'
make[2]: *** No targets specified and no makefile found. Stop.
make[2]: Leaving directory '/home/debian/beagleg/am335x_pru_package'
Makefile:141: recipe for target '../am335x_pru_package/pru_sw/utils/pasm' failed
make[1]: *** [../am335x_pru_package/pru_sw/utils/pasm] Error 2
make[1]: Leaving directory '/home/debian/beagleg/src'
Makefile:32: recipe for target 'all' failed
make: *** [all] Error 2

this means that you most probably forgot to clone the repository with the `--recursive` flag.

If that's the case, you can simply run inside the repository folder
`git submodule update --init --recursive` and run `make` again.

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