[[Category:ECE497]]
[[Category:SparkFun]]

<pre style="color:red">
Overview: 1, Don't just repeat the manual, tell me what you did.
Wiring: 0, Give details on how to wire it up. Show a diagram.
Code: 1, Comment you code and give details of how to use it.
git: 0, put in git
Demo: 2
Total: 4/10
Comments: Many details are missing. What would you need to tell a beginner
how to get this to go?
</pre>

== Overview ==

The PIR Motion Sensor can be purchased from [https://www.sparkfun.com/products/8630 SparkFun]. The [http://www.sparkfun.com/datasheets/Sensors/Proximity/SE-10.pdf datasheet] describes it:

''Easy-to-use motion detector with an analog interface. Power it with 5-12VDC, and you'll be alerted of any movement.''

I found this tutorial very helpful: [http://bildr.org/2011/06/pir_arduino/ Arduino Tutorial]

== Inputs and Outputs ==

This unit works great from 5 to 12V (datasheet shows 12V). You can also install a jumper wire past the 5V regulator on board to make this unit work at 3.3V. Sensor uses 1.6mA@3.3V.

== Bone Usage ==

=== Sample C Code ===

<pre>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <poll.h>
#include <signal.h>
#include <unistd.h>
#include "gpio.h"

/****************************************************************
* Constants
****************************************************************/

#define SYSFS_GPIO_DIR "/sys/class/gpio"
#define POLL_TIMEOUT (3 * 1000) /* 3 seconds */
#define MAX_BUF 64
/* {"gpio1_6", "gpio1_7", "gpio1_2", "gpio1_3", "gpio1_13", "gpio1_12", "gpio1_15", "gpio1_14"} */

/****************************************************************
* Global variables
****************************************************************/
int keepgoing = 1; // Set to 0 when ctrl-c is pressed

/****************************************************************
* signal_handler
****************************************************************/
// Callback called when SIGINT is sent to the process (Ctrl-C)
void signal_handler(int sig)
{
printf( "Ctrl-C pressed, cleaning up and exiting..\n" );
keepgoing = 0;
}

/****************************************************************
* main
****************************************************************/
int main(int argc, char **argv)
{
struct pollfd fdset[2];
int nfds = 2;
int gpio_fd, timeout, rc;
char *buf[MAX_BUF];
unsigned int gpio;
int len;

if (argc < 2) {
printf("Usage: gpio-int <gpio-pin>\n\n");
printf("Waits for a change in the GPIO pin voltage level or input on stdin\n");
exit(-1);
}

// Set the signal callback for Ctrl-C
signal(SIGINT, signal_handler);

gpio = atoi(argv[1]);

gpio_export(gpio);
gpio_set_dir(gpio, 0);
gpio_set_edge(gpio, "falling"); // Can be rising, falling or both
gpio_fd = gpio_fd_open(gpio);

timeout = POLL_TIMEOUT;

while (keepgoing) {
memset((void*)fdset, 0, sizeof(fdset));

fdset[0].fd = STDIN_FILENO;
fdset[0].events = POLLIN;

fdset[1].fd = gpio_fd;
fdset[1].events = POLLPRI;

rc = poll(fdset, nfds, timeout);

if (rc < 0) {
printf("\npoll() failed!\n");
return -1;
}

if (rc == 0) {
printf(".");
}

if (fdset[1].revents & POLLPRI) {
lseek(fdset[1].fd, 0, SEEK_SET); // Read from the start of the file
len = read(fdset[1].fd, buf, MAX_BUF);
printf("\nMotion Detected, value=%c, len=%d\n",
buf[0], len);
usleep(5000000);
}

if (fdset[0].revents & POLLIN) {
(void)read(fdset[0].fd, buf, 1);
printf("\npoll() stdin read 0x%2.2X\n", (unsigned int) buf[0]);
}

fflush(stdout);
}

gpio_fd_close(gpio_fd);
return 0;
}
</pre>

ECE497 Beagle VNS

2012-10-15T19:08:22Z

Atniptw: /* Conclusions */

[[Category:ECE497 |Project]]
{{YoderHead}}

Team members: [[user:Yoder|Mark A. Yoder]], (List all the team members here with link to their eLinux User page. Use my format.

== Executive Summary ==

We wanted a way for students to be able to leave audio (and possibly video) messages for professors when they are out of their office. Using a BeagleBoard Bone, we plan to connect a wireless USB device and a PlayStation Eye to achieve this. Students will be able to walk up to the device and press a button to record their message which will then be available for the professor.

Give two sentences telling what works.
Nothing

Give two sentences telling what isn't working.
All of it

End with a two sentence conclusion.
We will probably learn things

== Installation Instructions ==

Give step by step instructions on how to install your project on the SPEd2 image.

* Include your [https://github.com/ github] path as a link like this: [https://github.com/MarkAYoder/gitLearn https://github.com/MarkAYoder/gitLearn].
* Include any additional packages installed via '''opkg'''.
* Include kernel mods.
* If there is extra hardware needed, include links to where it can be obtained.

== User Instructions ==

Once everything is installed, how do you use the program? Give details here, so if you have a long user manual, link to it here.

== Highlights ==

Here is where you brag about what your project can do.

Include a [http://www.youtube.com/ YouTube] demo.

== Theory of Operation ==

Give a high level overview of the structure of your software. Are you using GStreamer? Show a diagram of the pipeline. Are you running multiple tasks? Show what they do and how they interact.

== Work Breakdown ==

List the major tasks in your project and who did what.

Also list here what doesn't work yet and when you think it will be finished and who is finishing it.

# Acquire Hardware - Ruffin
# Set up project page - Tom&Kevin
# Get USB wireless to work
# Get PlayStation Eye to work
# Get BeagleBoard Bone to run off a battery pack
# Register an email for the BeagleBoard
# Program stuff....
# Build stuff......

== Future Work ==

Suggest addition things that could be done with this project.

# Flame decals
# Spoiler
# Bigger Engine
# Sentient

== Conclusions ==

Give some concluding thoughts about the project. Suggest some future additions that could make it even more interesting. Need More Cake

{{YoderFoot}}

ECE497 Beagle VNS

2012-10-15T19:07:52Z

Atniptw: /* Conclusions */

2012-09-27T15:48:49Z

Atniptw:

[[Category:ECE497, Sparkfun]]

== Overview ==

The PIR Motion Sensor can be purchased from [https://www.sparkfun.com/products/8630 SparkFun]. The [http://www.sparkfun.com/datasheets/Sensors/Proximity/SE-10.pdf datasheet] describes it:

''Easy-to-use motion detector with an analog interface. Power it with 5-12VDC, and you'll be alerted of any movement.''

[http://bildr.org/2011/06/pir_arduino/ Arduino Tutorial]

== Inputs and Outputs ==

This unit works great from 5 to 12V (datasheet shows 12V). You can also install a jumper wire past the 5V regulator on board to make this unit work at 3.3V. Sensor uses 1.6mA@3.3V.

== Bone Usage ==

=== Sample C Code ===

<pre>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <poll.h>
#include <signal.h>
#include <unistd.h>
#include "gpio.h"

/****************************************************************
* Constants
****************************************************************/

#define SYSFS_GPIO_DIR "/sys/class/gpio"
#define POLL_TIMEOUT (3 * 1000) /* 3 seconds */
#define MAX_BUF 64
/* {"gpio1_6", "gpio1_7", "gpio1_2", "gpio1_3", "gpio1_13", "gpio1_12", "gpio1_15", "gpio1_14"} */

/****************************************************************
* Global variables
****************************************************************/
int keepgoing = 1; // Set to 0 when ctrl-c is pressed

/****************************************************************
* signal_handler
****************************************************************/
// Callback called when SIGINT is sent to the process (Ctrl-C)
void signal_handler(int sig)
{
printf( "Ctrl-C pressed, cleaning up and exiting..\n" );
keepgoing = 0;
}

/****************************************************************
* main
****************************************************************/
int main(int argc, char **argv)
{
struct pollfd fdset[2];
int nfds = 2;
int gpio_fd, timeout, rc;
char *buf[MAX_BUF];
unsigned int gpio;
int len;

if (argc < 2) {
printf("Usage: gpio-int <gpio-pin>\n\n");
printf("Waits for a change in the GPIO pin voltage level or input on stdin\n");
exit(-1);
}

// Set the signal callback for Ctrl-C
signal(SIGINT, signal_handler);

gpio = atoi(argv[1]);

gpio_export(gpio);
gpio_set_dir(gpio, 0);
gpio_set_edge(gpio, "falling"); // Can be rising, falling or both
gpio_fd = gpio_fd_open(gpio);

timeout = POLL_TIMEOUT;

while (keepgoing) {
memset((void*)fdset, 0, sizeof(fdset));

fdset[0].fd = STDIN_FILENO;
fdset[0].events = POLLIN;

fdset[1].fd = gpio_fd;
fdset[1].events = POLLPRI;

rc = poll(fdset, nfds, timeout);

if (rc < 0) {
printf("\npoll() failed!\n");
return -1;
}

if (rc == 0) {
printf(".");
}

if (fdset[1].revents & POLLPRI) {
lseek(fdset[1].fd, 0, SEEK_SET); // Read from the start of the file
len = read(fdset[1].fd, buf, MAX_BUF);
printf("\nMotion Detected, value=%c, len=%d\n",
buf[0], len);
usleep(5000000);
}

if (fdset[0].revents & POLLIN) {
(void)read(fdset[0].fd, buf, 1);
printf("\npoll() stdin read 0x%2.2X\n", (unsigned int) buf[0]);
}

fflush(stdout);
}

gpio_fd_close(gpio_fd);
return 0;
}
</pre>

ECE497 Contributions and Project Status here

2012-09-11T19:39:47Z

Atniptw:

{|
|-
! Name
! git repository
|-
| [[User:hansenrl | Ross Hansen]]
| [https://github.com/hansenrl/ece497.git MiniProject01]
|-
| [[User:atniptw | Tom Atnip]]
| [[https://github.com/atniptw/ECE497 | ECE497 Repo]]
|-
|}

ECE497 Contributions and Project Status here

2012-09-11T19:39:26Z

Atniptw:

ECE497 Contributions and Project Status here

2012-09-11T19:38:56Z

Atniptw:

User:Atniptw

2012-09-10T15:52:53Z

Atniptw:

Thomas Atnip

Computer Science && Software Engineering Major, Class of 2013.

== Projects ==
Project topics I'm interested in:
* Autonomous Drones - Beyond the scope of this class, but an area I find interesting

== Mini-projects ==

== How To ==
* [[ECE497: How to install Ubuntu on the Beagleboard]]

Derived from [[User:Mayhewsw | Stephen Mayhew]] page
[[Category:ECE497]]

EBC Exercise 10 Flashing an LED

2012-09-09T17:55:27Z

Atniptw: /* Analog in - bone */

[[Category:EmbeddedBeagleClass]]
[[Category:ECE497]]
{{YoderHead}}

The [http://en.wikipedia.org/wiki/Hello_world_program "Hello World"] program is the traditional first program for many classes. Flashing an LED is the embedded equivalent. Here we will explore a few ways to flash and LED on the Beagle and explore General Purpose I/O (gpio) along the way. This will call be done from the command line of the Beagle, so there is no need for the host computer.

== gpio via the Shell Command Line and sysfs ==

('''Note''': Draw the new diagrams with [http://engineersofthecorn.blogspot.com/2012/06/fritzing-part-for-beaglebone.html this].)

The easiest way to do general purpose I/O (gpio) on the Beagle is through a terminal window and a shell prompt. In Linux most everything is treated as a file. Even things that aren't files. In our class we'll use a virtual file system called '''sysfs'''. sysfs exposes the drivers for the hardware so you get easily use them.

Try this, open a terminal and type:

beagle$ '''cd /sys'''
beagle$ '''ls -F'''
block/ bus/ class/ dev/ devices/ firmware/ fs/ kernel/ module/ power/

Here we see several directories that represent hardware we can control. Explore a bit and see what you find.

Now try:

beagle$ '''cd /sys/class'''
beagle$ '''ls -F'''
bccat/ hwmon/ mtd/ scsi_disk/ usb_device/
bdi/ i2c-adapter/ net/ scsi_generic/ usbmon/
block/ i2c-dev/ omap-previewer/ scsi_host/ vc/
bluetooth/ input/ omap-resizer/ sound/ video4linux/
bsg/ leds/ pvr/ spi_master/ vtconsole/
display/ mdio_bus/ regulator/ spidev/
firmware/ mem/ rfkill/ thermal/
gpio/ misc/ rtc/ tty/
graphics/ mmc_host/ scsi_device/ ubi/

Explore some. What do you find? In '''graphics''' you will see the 3 frame buffers supported by the processor. In '''sound''' you'll see the [http://www.alsa-project.org/main/index.php/Main_Page alsa] sound devices.

== Flashing the user LEDs ==

The Beagle xM has two user LEDS, '''user0''' and '''user1''', that you can control. The Bone has 4. Try this:

beagle$ '''cd /sys/class/leds'''
beagle$ '''ls -F'''
beaglebeagleboard::pmu_stat@ beagleboard::usr0@ beagleboard::usr1@

Here you see the directories for controlling each of the usr LEDs. By default, usr0 flashes a heartbeat pattern and usr1 flashes when the micro SD card is accessed. Let's control usr0.

beagle$ '''cd beagleboard\:\:usr0'''
beagle$ '''ls -F'''
brightness device@ max_brightness power/ subsystem@ trigger uevent

See what's in '''brightness''', '''max_brightness''' and '''trigger''' by using the <code>cat</code> command. For example:

beagle$ '''cat trigger'''
none nand-disk mmc0 [heartbeat]

This shows trigger can have 4 values. The present value is '''heartbeat'''. Check the LED, is the beating? You can stop the heartbeat via:

beagle$ '''echo none > trigger'''
beagle$ '''cat trigger'''
[none] nand-disk mmc0 heartbeat

Did it stop beating? You can now turn it on and off with:

beagle$ '''echo 1 > brightness'''
beagle$ '''echo 0 > brightness'''

Is it responding correctly?

The Bone has more trigger options. Try:

beagle$ '''cat trigger'''
[none] mmc0 timer heartbeat backlight gpio default-on
beagle$ '''echo timer > trigger'''
brightness delay_on max_brightness subsystem uevent
delay_off device power trigger
beagle$ '''echo 100 > delay_on'''
beagle$ '''echo 900 > delay_off'''

What does this do?

== Adding your own LED - bone ==

It's not hard to use the gpio pins to control your own LED. All you need is an LED and a 220Ω resistor. Here's a picture of how it's wired. We are just doing the LED at the top of the breadboard for now.

[[File:Bone gpio.JPG|300px]]
[[File:BoneGPIO.png|300px]]

So how do you know where to connect it? The BeagleBone [http://beagleboard.org/static/beaglebone/latest/Docs/Hardware/BONE_SRM.pdf System Reference Manual] has the details. Figure 3 on page 18 of RevA5.01 shows:

[[File:Beagle Bone.jpg|300px]]

There at two expansion headers, P8 and P9. Look at the bottom of the left header and you'll see it's labeled '''P9'''. Table 11 on page 59 shows the pinout for P9.

[[File:Bone P9 pinout.jpg|400px]]

On the first photo above you can see that pin 1 (Ground) is wired to the '''-''' bus and pin 3 (3.3V) is wired to the '''+''' bus. The 220Ω resistor is wired to the '''-''' bus and the other end is attached to the negative lead of the LED. The positive lead is attached to pin 12 which, as shown in Table 11, is attached to '''gpio1_28'''. The gpio pins are in banks of 32 each, so to find the gpio number to use on the Beagle, use 1*32+28='''60'''. Here's how you turn it on

beagle$ '''cd /sys/class/gpio'''
beagle$ '''ls'''
export gpiochip0 gpiochip32 gpiochip64 gpiochip96 unexport

Presently no gpio pins are visible. You need to tell it which pin to export

beagle$ '''echo 60 > export'''
beagle$ '''ls'''
gpio60 gpiochip0 gpiochip32 gpiochip64 gpiochip96

Notice '''gpio60''' has appeared. All we need to do is tell it which direction and then turn it on.

beagle$ '''cd gpio60'''
beagle$ '''echo out > direction'''
beagle$ '''echo 1 > value'''

Your LED should be on! When you are done you can unexport the pin and it will disappear.
beagle$ cd ..
beagle$ '''echo 60 > unexport'''

== Reading a switch - bone ==

Now that you have an LED working, wiring in a switch is easy. The picture above shows a push button switch wired in at the bottom of the P9 header. Attach the '''+''' bus to one pole on the switch with a wire. The other end of the switch is attached to pin 42 which is '''gpio0_7'''.

Based on what you saw above, show how to read the switch.

Once you have the switch and LED working you can use the following scripts to play with them.

beagle$ '''cd ~/exercises/gpio'''
beagle$ '''./togglegpio.sh 60 0.1'''

The LED should be blinking on and off.

beagle$ '''./readgpio.sh 7'''

Push the pushbutton and see what happens.

How can this work without a pulldown resistor? It turns out the Bone has an internal pulldown (and up) resistor that can be software enabled. Try:

beagle$ '''cd /sys/kernel/debug/omap_mux'''
beagle$ '''ls'''
ain0 gpmc_ad2 lcd_data3 mii1_txd2
ain1 gpmc_ad3 lcd_data4 mii1_txd3
ain2 gpmc_ad4 lcd_data5 mii1_txen
ain3 gpmc_ad5 lcd_data6 mmc0_clk
ain4 gpmc_ad6 lcd_data7 mmc0_cmd
ain5 gpmc_ad7 lcd_data8 mmc0_dat0
ain6 gpmc_ad8 lcd_data9 mmc0_dat1
ain7 gpmc_ad9 lcd_hsync mmc0_dat2
board gpmc_advn_ale lcd_pclk mmc0_dat3
ecap0_in_pwm0_out gpmc_ben0_cle lcd_vsync rmii1_refclk
emu0 gpmc_ben1 mcasp0_aclkr spi0_cs0
emu1 gpmc_clk mcasp0_aclkx spi0_cs1
gpmc_a0 gpmc_csn0 mcasp0_ahclkr spi0_d0
gpmc_a1 gpmc_csn1 mcasp0_ahclkx spi0_d1
gpmc_a10 gpmc_csn2 mcasp0_axr0 spi0_sclk
gpmc_a11 gpmc_csn3 mcasp0_axr1 uart0_ctsn
gpmc_a2 gpmc_oen_ren mcasp0_fsr uart0_rtsn
gpmc_a3 gpmc_wait0 mcasp0_fsx uart0_rxd
gpmc_a4 gpmc_wen mdio_clk uart0_txd
gpmc_a5 gpmc_wpn mdio_data uart1_ctsn
gpmc_a6 i2c0_scl mii1_col uart1_rtsn
gpmc_a7 i2c0_sda mii1_crs uart1_rxd
gpmc_a8 lcd_ac_bias_en mii1_rxclk uart1_txd
gpmc_a9 lcd_data0 mii1_rxd0 usb0_drvvbus
gpmc_ad0 lcd_data1 mii1_rxd1 usb1_drvvbus
gpmc_ad1 lcd_data10 mii1_rxd2 vrefn
gpmc_ad10 lcd_data11 mii1_rxd3 vrefp
gpmc_ad11 lcd_data12 mii1_rxdv xdma_event_intr0
gpmc_ad12 lcd_data13 mii1_rxerr xdma_event_intr1
gpmc_ad13 lcd_data14 mii1_txclk
gpmc_ad14 lcd_data15 mii1_txd0
gpmc_ad15 lcd_data2 mii1_txd1
beagle$ '''ls | wc'''
125 125 1220

Here you will find a list of how all the pin muxes are set. There are some 125 of them!
How do you find which one is gpio0_7?

beagle$ '''grep gpio0_7 *'''
ecap0_in_pwm0_out:name: ecap0_in_pwm0_out.gpio0_7 (0x44e10964/0x964 = 0x0027), b NA, t NA
''ecap0_in_pwm0_out'':signals: ecap0_in_pwm0_out | uart3_txd | spi1_cs1 | pr1_ecap0_ecap_capin_apwm_o | spi1_sclk | mmc0_sdwp | xdma_event_intr2 | ''gpio0_7''

'''ecap0_in_pwm0_out''' is the file that contains gpio0_7. Look up gpio0_7

beagle$ '''cat ecap0_in_pwm0_out'''
name: ecap0_in_pwm0_out.gpio0_7 (0x44e10964/0x964 = 0x0027), b NA, t NA
mode: ''OMAP_PIN_INPUT_PULLDOWN'' | OMAP_MUX_MODE7
signals: ecap0_in_pwm0_out | uart3_txd | spi1_cs1 | pr1_ecap0_ecap_capin_apwm_o | spi1_sclk | mmc0_sdwp | xdma_event_intr2 | gpio0_7

It's set to be a PULLDOWN. Sectiion 9.2.2.2, Page 877 of the AM335x Technical Reference manual discusses Pull Selection and tells which bits do what. The '''0x0027''' is the code that says which MODE is used and how the pull up/down resistor is set. (There seems to be a mismatch between the manual and the bone. The manual says bit 3 of 0x0027 enables the pull up/down. Bit 3 isn’t set, but the pull down is working.)

You can switch the gpio pin to pullup. Try

beagle$ '''echo 0x0037 > ecap0_in_pwm0_out'''
beagle$ '''cat ecap0_in_pwm0_out'''
name: ecap0_in_pwm0_out.gpio0_7 (0x44e10964/0x964 = 0x0037), b NA, t NA
mode: OMAP_PIN_INPUT_PULLUP | OMAP_MUX_MODE7
signals: ecap0_in_pwm0_out | uart3_txd | spi1_cs1 | pr1_ecap0_ecap_capin_apwm_o | spi1_sclk | mmc0_sdwp | xdma_event_intr2 | gpio0_7

Does it act like a pullup resistor is attached?

=== Challenge ===

* Can you modify the scripts above to read the switch and turn the LED on and off?
* Rewire your switch to work will a pullup resistor.

== Analog in - bone ==

(This is based on [http://www.gigamegablog.com/2012/01/22/beaglebone-coding-101-using-the-serial-and-analog-pins/ this].)

The bone has eight Analog Inputs. Several are exposed on P9. They are labeled '''AIN''' in table 11 above. How many do you find?

The AIN pins are sampled at 12 bits and 100k samples per second. The input voltage is between 0 and 1.8V. Fortunately, both voltages are available on P9.

The photo above shows a small potentiometer wired to the bone. One end goes to the analog ground (pin 34), the other analog 1.8V (pin 32). The wiper is attached to '''AIN5''' which is pin 36.

You interact with the analog in much like the gpio, but it appears in a different location. How do you find that location? One approach is the '''find''' command.

beagle$ '''find / -name ain5'''
/sys/devices/platform/omap/tsc/ain5
/sys/kernel/debug/omap_mux/ain5
'''^C'''

I used '''Ctrl-C''' to interrupt since it already found what I wanted.

beagle$ '''cd /sys/devices/platform/omap/tsc'''
beagle$ '''ls'''
ain1 ain3 ain5 ain7 driver power uevent
ain2 ain4 ain6 ain8 modalias subsystem

There are the various analog inputs, but watch out. This interface starts numbering at '''1''' and Table 11 starts at '''0''', so to read AIN5 you need to look at '''ain6'''!

beagle$ '''cat ain6'''
1185

(Unfortunately the interface doesn't print a RETURN after the value.)
Change the pot and rerun the cat. What's the min and max value you get? Is it 12 bits?

=== Challenge ===
Rewrite the scripts from before to read an AIN pin and continuously display it's value.

== Reading a gpio pin with an Oscilloscope - xM ==

You can easily access many of the gpio pins via the Main Expansion Header. Page 107 of the [http://beagleboard.org/static/BBxMSRM_latest.pdf BeagleBoard-xM System Reference Manual] has this figure.
[[File:MainHeader.png | 750px]]

Unfortunately the gpio pins don't appear here. It turns out the processor has more internal I/O lines than it has physical pins. Each physical pin can can be connected to up to 8 internal lines. [[BeagleBoardPinMux]] does a nice job of explaining it all. The big clue is here [[BeagleBoardPinMux#Beagle]] which references Table 22 on page 108 of the -xM [http://beagleboard.org/static/BBSRM_latest.pdf System Reference Manual].

[[File:ExpansionSignals.png‎]]

Note that gpio130 appears on pin 21 of the Expansion Header. Also note that pins 27 and 28 are ground. Attach your scope probe to these. Now, let's put a signal on the pin.

beagle$ '''cd /sys/class/gpio'''
beagle$ '''ls -F'''
export gpiochip128@ gpiochip192@ gpiochip64@ unexport
gpiochip0@ gpiochip160@ gpiochip32@ gpiochip96@

Notice there is no folder for gpio130. Create it with:

beagle$ '''echo 130 > export'''
beagle$ '''ls -F'''
export gpiochip0@ gpiochip160@ gpiochip32@ gpiochip96@
gpio130@ gpiochip128@ gpiochip192@ gpiochip64@ unexport

Update your exercises folder and cd to gpio directory.

beagle$ '''cd'''
beagle$ '''cd exercises/gpio'''
beagle$ '''git pull'''
beagle$ '''gedit togglegpio.sh'''

Can you tell what the program is doing? Try running it:

beagle$ '''togglegpio 130 0.05'''

Note that if you are the root user (which is the default case for Angstrom), you will have to type the following command:

beagle$ '''./togglegpio 130 0.05'''

The first argument tells which gpio port to toggle, the second tells how long to delay between toggling. In this example 0.05 s is 50 ms, which should give a period around 100ms. Measure the signal on an oscilloscope.

== Assignment: gpio from the shell ==

=== Measuring a gpio pin on an Oscilloscope ===

Answer the following questions about gpio measurements.

# What's the min and max voltage?
# What period is it?
# How close is it to 100ms?
# Why do they differ?
# Run '''htop''' and see how much processor you are using.
# Try different values for the sleep time (2nd argument). What's the shortest period you can get? Make a table of the values you try and the corresponding period and processor usage.
# How stable is the period?
# Try launching something like '''mplayer'''. How stable is the period?
# Try cleaning up togglegpio and removing unneeded lines. Does it impact the period?
# togglegpio uses bash (first line in file). Try using sh. Is the period shorter?
# What's the shortest period you can get?

=== Toggling the LEDs ===

Modify togglegpio (call it toggleLED) to toggle the LEDs. Can you get the LED to appear to dim by changing the duty cycle of the toggling?

=== User Button to gpio 130 ===

Write a shell script that reads the User Button and outputs it value on gpio pin 130.

=== Count the User Button Presses ===

Write a shell script that displays a count of the number of times the User Button has been pressed.

=== Copy gpio 130 to gpio 131 ===

Write a shell script that copies the value of gpio pin 130 to gpio pin 131. How much CPU time does it take? What's the delay from the time the input changes until the output changes? How constant is the delay?

== Additional Exercises ==

=== Reading the Keyboard and Mouse ===
Try this:

beagle$ '''cd /sys/class/input'''
beagle$ '''ls -F'''
beagle$ '''evtest /dev/input/event2'''
Hit ctrl-C to stop

Now move your mouse around, or try you keyboard. My mouse is plugged into the bottom left USB port and event2 responds to it. Where do your keyboard and mouse appear?

=== Reading the User Button ===
('''Note''': This may not work on some versions of the OS. In these versions another program is controlling the gpio port that the User button is attached to.)

The Beagle has a couple of push buttons. One reboots the whole board. Use with care. One is for you to use, it's to the right of the Reset button, between the two stacks of USB ports.
[[File:BeagleUserButton.png]]

It's attached to gpio port 4. You can read it via:

beagle$ '''cd /sys/class/gpio'''
beagle$ '''ls -F'''
export gpio133@ gpio137@ gpio141@ gpiochip160@ gpiochip96@
gpio130@ gpio134@ gpio138@ gpio162@ gpiochip192@ unexport
gpio131@ gpio135@ gpio139@ gpiochip0@ gpiochip32@
gpio132@ gpio136@ gpio140@ gpiochip128@ gpiochip64@

Notice there is no gpio4. Here's how you can create it, set it to an input port and read its value:

beagle$ '''echo 4 > export'''
beagle$ '''ls'''
beagle$ '''cd gpio4'''
beagle$ '''echo in > direction'''
beagle$ '''cat value'''

Try holding down the switch and doing <code>cat value</code> again. Does the value change? There's a shell script called '''readgpio''' that repeatedly reads the switch.

beagle$ '''readgpio 4'''

Try pushing the switch. Does it work? Hit ctrl-C to stop. Look at readgpio. How does it work?

beagle$ '''which readgpio'''
beagle$ '''cp /usr/bin/readgpio ~'''
beagle$ '''gedit ~/readgpio'''

== Resources ==

# [http://wh1t3s.com/2009/05/14/reading-beagleboard-gpio/ Here] is wh1ts article on flashing an LED. It is referenced in the '''readgpio''' file that comes on the Beagle.
# [http://blog.makezine.com/archive/2009/02/blinking-leds-with-the-beagle-board.html?CMP=OTC-0D6B48984890 This] Make magazine article has a few more details.
# [http://www.avrfreaks.net/wiki/index.php/Documentation:Linux/GPIO#Getting_access_to_a_GPIO Here] in a gpio reference for Linux in general. It includes sample 'C' code for flashing at 1 Hz.
# [https://groups.google.com/forum/?hl=en#!msg/beagleboard/20rM-r8C2YY/hVZiN2ahI8YJ Here] is a posting in the Beagle Google group about gpio.
# [http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/gpio.txt;h=36af58eba136bac198ea3b1f33f34236be9ce5df;hb=HEAD Here] is some information about gpio from the kernel point of view.
# [http://wiki.gumstix.org/index.php?title=GPIO_Event_Driver Here] is some info on a GPIO Event Driver
# [https://www.ridgerun.com/developer/wiki/index.php/How_to_use_GPIO_signals Here] is info on how to set '''edge''' to falling and poll() the pin.
# [http://www.kernel.org/doc/Documentation/gpio.txt Here] is the kernel Documentation on gpio.

{{YoderFoot}}

ECE497 Contributions and Project Status

2012-09-04T15:56:12Z

Atniptw:

[[Category:ECE497 |Contributions]]
{{YoderHead}}

== Fall 2012 ==

=== Project Status ===

Please edit this page and add your project to this list. Copy my [[ECE497 Project Template]] to your own eLinux page and include the title of your project in the name of the page.

Please make the list alphabetical by family name.

Take a look at what you and others have contributed.

{|
|-
! Name
! Contributions
! Project
! git repository
|-
| [[User:atniptw | Tom Atnip]]
|
| [[ECE497 Project Template | My Beagle Project]]
| [https://github.com/atniptw/ atniptw]
|-
| [[User:larmorgs | Greg Larmore]]
|
| [[ECE497 Project Template | My Beagle Project]]
|
|-
| [[User:jessebrannon | Jesse Brannon]]
|
| [[ECE497 Project Template | My Beagle Project]]
|
|-
| [[User:duganje | Josh Dugan]]
|
| [[ECE497 duganje Project | My Beagle Project]]
|
|-
| [[User:Geislekj | Kevin Geisler]]
|
| [[ECE497 Project Template | My Beagle Project]]
| [https://github.com/geislekj/ geislekj]
|
|-
| [[User:chris.good | Christopher A Good]]
|
| [[ECE497 Project Template | My Beagle Project]]
|
|-
| [[User:hansenrl | Ross Hansen]]
| [[Special:Contributions/hansenrl|contrib]]
| [[ECE497 hansenrl Project | My Beagle Project]]
| [https://github.com/hansenrl/ Hansenrl]
|
|-
| [[User:jungeml | Michael Junge]]
|
| [[ECE497 jungeml Project | My Beagle Project]]
| [https://github.com/jungeml/ Jungeml]
|-
| [[User:mmoravec | Matthew Moravec]]
|
| [[ECE497 mmoravec Project | My Beagle Project]]
|
|-
| [[User:ngop | Peter Ngo]]
|
| [[ECE497 ngop Project | My Beagle Project]]
|
|-
| [[User:shinnsm|Stephen Shinn]]
| [[Special:Contributions/shinnsm|contrib]]
| Project TBD
| [https://github.com/shinnsm shinnsm]
|-
| [[User:ruff | Ruffin White]]
|
| [[ECE497 ruff Project | My Beagle Project]]
|
|-
| [[User:Yoder | Mark A. Yoder]]
| [[Special:Contributions/Yoder | contrib]]
| [[ECE497 Project Template | My Beagle Project]]
| [https://github.com/MarkAYoder MarkAYoder]
|-
| [[User:Popenhjc | James Popenhagen]]
|
| [[ECE497 popenhjc Project | My Beagle Project]]
|
|-
| [[User:Whiteer | Elias White]]
|
| [[ECE497 whiteer Project | My Beagle Project]]
|
|-
| [[User:Richarsm | Sean Richardson]]
|
| [[ECE497 richarsm Project | My Beagle Project]]
| [https://github.com/seanrich Sean Richardson]
|-
| [[User:Millerap | Andrew Miller]]
|
| [[ECE 497 millerap Project | My Beagle Project]]
|
|-
|}

== Winter 2011-2012 ==

=== Contributions ===

# [[Special:Contributions/Yuming | Yuming Cao]]
# [[Special:Contributions/Yifei | Yifei Li]]
# [[Special:Contributions/Harrisgw | Greg Harrison]]
# [[Special:Contributions/mac | Jack Ma]]
# [[Special:Contributions/Gemini91 | Guanqun Wang]]
# [[Special:Contributions/Yanj | Mona Yan]]
# [[Special:Contributions/Yoder | Mark A. Yoder]]
# [[Special:Contributions/Yuhasmj | Michael Yuhas]]
# [[Special:Contributions/Ziyi Zhang | Ziyi Zhang]]
# [[Special:Contributions/Zitnikdj | David Zitnik]]
# [[Special:Contributions/Zitnikdj | Alex Drane]]
# [[Special:Contributions/jessebrannon | Jesse Brannon]]

=== Project Status ===

# [[User:Yoder | Mark A. Yoder]], [[ECE497 Project Template | My Beagle Project]]
# [[user:Yanj|Mona Yan]] and [[user:Harrisgw| Greg Harrison]], [[PS EYE QT PROJECT | Playstation Eye Audio with Qt]]
# [[user:Caogecym | Yuming Cao]] and [[user:Ziyi Zhang | Ziyi Zhang]], [[Node.js Weather Station]]
# [[user:Yifei| Yifei Li]] and [[user:Gemini91| Guanqun Wang]], [[ Kinect Project | Play games using Kinect on Beagleboard]]
# [[user:Yuhasmj| Michael J. Yuhas]] and [[user:mac | Jack Ma]], [[ Multiple Partitions via U-boot | Multiple Partitions via U-boot ]]
# [[user:Zitnikdj| David Zitnik]], [[ ECE497 Project: Twitter Java Application | Twitter Java Application ]]

{{YoderFoot}}

ECE497 Contributions and Project Status

2012-07-20T23:42:59Z

Atniptw:

[[Category:ECE497 |Contributions]]
{{YoderHead}}

== Fall 2012 ==

=== Contributions ===
Please edit this page and add your user name, alphabetically by last name, to this list.

Take a look at what you and others have contributed.

# [[Special:Contributions/Yoder | Mark A. Yoder]]

=== Project Status ===

Please edit this page and add your project to this list. Copy my [[ECE497 Project Template]] to your own eLinux page and include the title of your project in the name of the page.

# [[User:atniptw | Tom Atnip]], [[ECE497 Project Template | My Beagle Project]]
# [[User:Yoder | Mark A. Yoder]], [[ECE497 Project Template | My Beagle Project]]

== Winter 2011-2012 ==

=== Contributions ===

# [[Special:Contributions/Yuming | Yuming Cao]]
# [[Special:Contributions/Yifei | Yifei Li]]
# [[Special:Contributions/Harrisgw | Greg Harrison]]
# [[Special:Contributions/mac | Jack Ma]]
# [[Special:Contributions/Gemini91 | Guanqun Wang]]
# [[Special:Contributions/Yanj | Mona Yan]]
# [[Special:Contributions/Yoder | Mark A. Yoder]]
# [[Special:Contributions/Yuhasmj | Michael Yuhas]]
# [[Special:Contributions/Ziyi Zhang | Ziyi Zhang]]
# [[Special:Contributions/Zitnikdj | David Zitnik]]

=== Project Status ===

# [[User:Yoder | Mark A. Yoder]], [[ECE497 Project Template | My Beagle Project]]
# [[user:Yanj|Mona Yan]] and [[user:Harrisgw| Greg Harrison]], [[PS EYE QT PROJECT | Playstation Eye Audio with Qt]]
# [[user:Caogecym | Yuming Cao]] and [[user:Ziyi Zhang | Ziyi Zhang]], [[Node.js Weather Station]]
# [[user:Yifei| Yifei Li]] and [[user:Gemini91| Guanqun Wang]], [[ Kinect Project | Play games using Kinect on Beagleboard]]
# [[user:Yuhasmj| Michael J. Yuhas]] and [[user:mac | Jack Ma]], [[ Multiple Partitions via U-boot | Multiple Partitions via U-boot ]]
# [[user:Zitnikdj| David Zitnik]], [[ ECE497 Project: Twitter Java Application | Twitter Java Application ]]

{{YoderFoot}}

User:Atniptw

2012-07-20T23:40:44Z

Atniptw:

User:Atniptw

2012-07-20T23:40:03Z

Atniptw:

User:Atniptw

2012-07-20T23:37:58Z

Atniptw: Created page with "Thomas Atnip Computer Science && Software Engineering Major, Class of 2013. == Projects == Project topics I'm interested in: * Autonomous Drones - Beyond the scope of this clas..."

ECE497 Editing a Wiki

2012-07-20T23:34:02Z

Atniptw:

[[Category:ECE497]]
{{YoderHead}}

Here is a wiki you can practice editing. Before you can edit it you will have to create an login. Pick something that will make it easy for me to identify you as part of my class. Then just add your name and date on the end of the table.

You can get help here: [[Help:Contents]].

If you need help with syntax check out the [[Editing Quickstart Guide|eLinux guide]] or the [http://en.wikipedia.org/wiki/Wikipedia:Cheatsheet Wikipedia Cheatsheet].

== Fall 2012 ==

{|
|-
| [[user:Yoder | Mark A. Yoder]]
| 18-July-2012
|-
| [[user:atniptw | Tom Atnip]]
| 20-July-2012
|-
|
|
|}

== Winter 2011-2012 ==

{|
|-
| [[user:Yoder | Mark A. Yoder]]
| 21-Nov-2011
|-
| [[user:Yuming | Yuming Cao]]
| 21-Nov-2011
|-
| [[user:Yuhasmj | Michael Yuhas]]
| 21-Nov-2011
|-
| [[user:Yifei | Yifei Li]]
| 22-Nov-2011
|-
| [[user:Ziyi Zhang | Ziyi Zhang]]
| 24-Nov-2011
|-
|[[user: mac | Jack Ma]]
| 28-Nov-2011
|-
| [[user:Zitnikdj | David Zitnik]]
| 25-Nov-2011
|-
| [[user:Harrisgw | Greg Harrison]]
| 26-Nov-2011
|-
| [[user:Yanj | Mona J Yan]]
| 27-Nov-2011
|-
| [[user:Gemini91 | Guanqun Wang]]
| 28-Nov-2011
|-
| [[user:vsn1985 | Narayanan VS]]
| 28-Nov-2011
|}

{{YoderFoot}}

ECE497 Signup

2012-04-27T02:18:42Z

Atniptw:

[[Category:ECE497]]

This page is for those who are interested in my ECE497 class. Please add your name to the list by copying the blank line at the end and adding your information. Please leave a blank line at the end.

Adding your name here doesn't put you in the class. I want to talk to you first before adding to the official class list.

{| style="color:green; background-color:#ffffcc;" cellpadding="10" cellspacing="0" border="1"
! Name
! Major
! Year
! Have you had an OS class? Which one(s)?
! Have you had an embedded class? Which one(s)?
! Linux experience

0 = What's Linux

5 = Used it in OS

10 = Written Drivers
! Open Source Experience
|-
| Mark A. Yoder
| ECE
| Faculty
| Yes
| Yes
| 9
| Much
|-
| Matt Fuson
| ECE
| Junior
| No
| Yes (ECE230,ECE333)
| 4
| Program Arduino in spare time.
|-
| Tom Atnip
| CS/SE
| Junior (Current)
| Yes (CSSE332)
| Yes (CSSE232)
| 7
| Open Source Project W/ Last Internship
|-
|
|
|
|
|
|
|
|}