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KenUnix
Apr 6, 2020, 8:33:41 PM4/6/20
to BeagleBoard
Could someone display an example of operating and releasing a relay in 'c'?
And if possible getting the current state of the relay. Operated or released
.
I have the relay cape from Mouser 958-RLYCPE-BBBCAPE GHI installed.
Relay Cape. From what I read.
Relay 1 gpio20
Relay 2 gpio 7
Relay 3 gpio112
Relay 4 gpio115
If possible code not requiring libraries or header files not normally on the BBB image (RCN 10.3 Debian IoT)
unless I can download any required files from a URL.
Thanks
This is what I found so far (thanks zmatt)
relay 1 - P9.41 - gpio 0.20 (gpio20)
relay 2 - P9.42 - gpio 0.07 (gpio7)
relay 3 - P9.30 - gpio 3.16 (gpio112)
relay 4 - P9.27 - gpio 3.19 (gpio115)
relay 2 - P9.42 - gpio 0.07 (gpio7)
relay 3 - P9.30 - gpio 3.16 (gpio112)
relay 4 - P9.27 - gpio 3.19 (gpio115)
Mala Dies
Apr 6, 2020, 9:07:13 PM4/6/20
to BeagleBoard
Hello KenUnix,
Seth here. I will need to type one up. I found a book a while back on setting up GPIO pins in C/C++ (more towards C than C++). Anyway...
I think I can assist in this matter.
...
I think that Adafruit_BBIO and some other libraries might go extinct soon. I am not familiar enough w/ Python to write my own library just yet.
I am not familiar enough w/ C/C++ to type up an entire library yet either, e.g. mostly due to headers in C/C++ and import OS and others in Python.
Seth
P.S. Anyway, the book is Exploring BeagleBone by Molloy. I will get on this task soon. Please bear w/ me on this endeavor.
jonnymo
Apr 6, 2020, 10:41:40 PM4/6/20
to Beagle Board
I suspect this is the Relay board you have:
Have you looked at?
Mala had recently posted questions regarding this board. Have you seen this:
Also, which Beagle Board are you connecting this to?
Relay,
Jon
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KenUnix
Apr 6, 2020, 11:19:49 PM4/6/20
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Jon,
Yes Mala I.E. Seth have exchanged messages
The 'c' I tried refuses to operate relays
--Start code--
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
int main()
{
int fd = open( "/sys/class/gpio/gpio112/value", O_RDWR | O_CLOEXEC );
if( fd < 0 ) {
fprintf( stderr, "open: %m\n" );
exit(1);
}
char c = '1';
write( fd, &c, 1 );
close( fd );
return 0;
}
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
int main()
{
int fd = open( "/sys/class/gpio/gpio112/value", O_RDWR | O_CLOEXEC );
if( fd < 0 ) {
fprintf( stderr, "open: %m\n" );
exit(1);
}
char c = '1';
write( fd, &c, 1 );
close( fd );
return 0;
}
--End Code--
No errors. Just dosen't do anything
Ken
Robert Nelson
Apr 6, 2020, 11:24:06 PM4/6/20
to Beagle Board, Kenneth Martin
Your trying too hard..
Turn Relay 2 on:
echo 1 > /sys/class/leds/relay-jp2/brightness
Turn Relay 2 off:
echo 0 > /sys/class/leds/relay-jp2/brightnessRegards,
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jonnymo
Apr 6, 2020, 11:56:22 PM4/6/20
to Beagle Board, Kenneth Martin
Robert,
Out of curiosity, does that require having the Relay overlay loaded or is that a default?
Cheers,
Jon
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Dennis Lee Bieber
Apr 7, 2020, 11:58:26 AM4/7/20
to Beagleboard
On Mon, 6 Apr 2020 20:19:49 -0700 (PDT), in
gmane.comp.hardware.beagleboard.user KenUnix
code I've seen make use of higher level file pointer calls.
https://stackoverflow.com/questions/34261512/gpio-on-beaglebone-black
{somewhat odd that that example does a SEEK to beginning, for files opened
"w", but does not do a seek within the loop when toggling the GPIO value}
I'll admit most of my experiments have been using Python (and I do not
envisage Adafruit_BBIO just vanishing some day... not unless it too gets
subsumed into CircuitPython via Blinka library [a lot of the former device
specific libraries have gone that route]).
No experience with https://github.com/ehayon/BeagleBone-GPIO which
bypasses the sysfs calls for memory-mapping the GPIO system.
https://www.beyondlogic.org/an-introduction-to-chardev-gpio-and-libgpiod-on-the-raspberry-pi/
focuses on the R-Pi, but ...
debian@beaglebone:~$ apt-cache search gpiod
gpiod - Tools for interacting with Linux GPIO character device - binary
gpiod-dbgsym - debug symbols for gpiod
libgpiod-dev - C library for interacting with Linux GPIO device - static
libraries and headers
libgpiod-doc - C library for interacting with Linux GPIO device - library
documentation
libgpiod0 - C library for interacting with Linux GPIO device - shared
libraries
libgpiod0-dbgsym - debug symbols for libgpiod0
libgpiod1 - C library for interacting with Linux GPIO device - shared
libraries
libgpiod1-dbgsym - debug symbols for libgpiod1
libgpiod2 - C library for interacting with Linux GPIO device - shared
libraries
libgpiod2-dbgsym - debug symbols for libgpiod2
python3-libgpiod - Python bindings for libgpiod (Python 3)
python3-libgpiod-dbgsym - debug symbols for python3-libgpiod
debian@beaglebone:~$
... seems to be available on BBB -- no idea what the 0/1/2 variants are...
(unfortunately, the link mentions the C API, but doesn't show an example)
>
>No errors. Just dosen't do anything
>
Take off the relay board and just wire in an LED and limit resistor
between the GPIO and ground (or 3.3V depending on whether you want "set" to
be on or off) and see if the LED flickers.
--
Dennis L Bieber
gmane.comp.hardware.beagleboard.user KenUnix
<ken.unix.guy-Re5J...@public.gmane.org> wrote:
> int fd = open( "/sys/class/gpio/gpio112/value", O_RDWR | O_CLOEXEC );
I note you are using the low-level file descriptor calls, whereas most
> int fd = open( "/sys/class/gpio/gpio112/value", O_RDWR | O_CLOEXEC );
code I've seen make use of higher level file pointer calls.
https://stackoverflow.com/questions/34261512/gpio-on-beaglebone-black
{somewhat odd that that example does a SEEK to beginning, for files opened
"w", but does not do a seek within the loop when toggling the GPIO value}
I'll admit most of my experiments have been using Python (and I do not
envisage Adafruit_BBIO just vanishing some day... not unless it too gets
subsumed into CircuitPython via Blinka library [a lot of the former device
specific libraries have gone that route]).
No experience with https://github.com/ehayon/BeagleBone-GPIO which
bypasses the sysfs calls for memory-mapping the GPIO system.
https://www.beyondlogic.org/an-introduction-to-chardev-gpio-and-libgpiod-on-the-raspberry-pi/
focuses on the R-Pi, but ...
debian@beaglebone:~$ apt-cache search gpiod
gpiod - Tools for interacting with Linux GPIO character device - binary
gpiod-dbgsym - debug symbols for gpiod
libgpiod-dev - C library for interacting with Linux GPIO device - static
libraries and headers
libgpiod-doc - C library for interacting with Linux GPIO device - library
documentation
libgpiod0 - C library for interacting with Linux GPIO device - shared
libraries
libgpiod0-dbgsym - debug symbols for libgpiod0
libgpiod1 - C library for interacting with Linux GPIO device - shared
libraries
libgpiod1-dbgsym - debug symbols for libgpiod1
libgpiod2 - C library for interacting with Linux GPIO device - shared
libraries
libgpiod2-dbgsym - debug symbols for libgpiod2
python3-libgpiod - Python bindings for libgpiod (Python 3)
python3-libgpiod-dbgsym - debug symbols for python3-libgpiod
debian@beaglebone:~$
... seems to be available on BBB -- no idea what the 0/1/2 variants are...
(unfortunately, the link mentions the C API, but doesn't show an example)
>
>No errors. Just dosen't do anything
>
between the GPIO and ground (or 3.3V depending on whether you want "set" to
be on or off) and see if the LED flickers.
--
Dennis L Bieber
KenUnix
Apr 7, 2020, 12:39:56 PM4/7/20
to BeagleBoard
Robert,
You were correct high level is better for now. It's been a long while since working
with 'c'. Went the way of a bash script. Works well see below. Even supports --help.
---Code Start--
#!/bin/bash
#
# 4-7-2020 Ken
#
# cmd [state|label|on|off|in|out] gpio #
# Example : cmd state 112
#
if [ "$1" == "--help" ]
then
echo -e "\ngpio relay cape tool. 4-7-2020 KenUnix\n"
echo "state Get state of gpio number"
echo "label Display associated P number"
echo "on Set relay # to on"
echo "off Turn relay off"
echo -e "out Set gpio to out\n"
echo "Example: cmd status 115 Will display the state of gpio 115"
echo -e " cmd on 20 Will turn relay 1 on for gpio 20\n"
exit
fi
case $2 in
20|7|112|115) ;;
*) echo "Invalid gpio $2"
echo "Vaild numbers are 20, 7, 112 or 115"
echo -e "Relay 1 20, relay 2 7, relay 3 112, relay 4 115\007"
exit 1 ;;
esac
case $1 in
"state")
direction=`cat /sys/class/gpio/gpio$2/direction`
echo -n "Direction $direction, State "
state=`cat /sys/class/gpio/gpio$2/value`
if [ "$state" == "0" ]; then echo "off"; fi
if [ "$state" == "1" ]; then echo "on"; fi
exit ;;
"label")
echo -n "Physical header pin number "
cat /sys/class/gpio/gpio$2/label ;
exit ;;
"on")
echo 1 >/sys/class/gpio/gpio$2/value
exit ;;
"off")
echo 0 >/sys/class/gpio/gpio$2/value
exit ;;
"out")
echo "out" > /sys/class/gpio/gpio$2/direction ;
exit ;;
"in")
echo "in" > /sys/class/gpio/gpio$2/direction ;
exit ;;
*) echo -e "Invalid operation $1. Try cmd --help\007" ; exit 1 ;;
esac
--Code End--
#
# 4-7-2020 Ken
#
# cmd [state|label|on|off|in|out] gpio #
# Example : cmd state 112
#
if [ "$1" == "--help" ]
then
echo -e "\ngpio relay cape tool. 4-7-2020 KenUnix\n"
echo "state Get state of gpio number"
echo "label Display associated P number"
echo "on Set relay # to on"
echo "off Turn relay off"
echo -e "out Set gpio to out\n"
echo "Example: cmd status 115 Will display the state of gpio 115"
echo -e " cmd on 20 Will turn relay 1 on for gpio 20\n"
exit
fi
case $2 in
20|7|112|115) ;;
*) echo "Invalid gpio $2"
echo "Vaild numbers are 20, 7, 112 or 115"
echo -e "Relay 1 20, relay 2 7, relay 3 112, relay 4 115\007"
exit 1 ;;
esac
case $1 in
"state")
direction=`cat /sys/class/gpio/gpio$2/direction`
echo -n "Direction $direction, State "
state=`cat /sys/class/gpio/gpio$2/value`
if [ "$state" == "0" ]; then echo "off"; fi
if [ "$state" == "1" ]; then echo "on"; fi
exit ;;
"label")
echo -n "Physical header pin number "
cat /sys/class/gpio/gpio$2/label ;
exit ;;
"on")
echo 1 >/sys/class/gpio/gpio$2/value
exit ;;
"off")
echo 0 >/sys/class/gpio/gpio$2/value
exit ;;
"out")
echo "out" > /sys/class/gpio/gpio$2/direction ;
exit ;;
"in")
echo "in" > /sys/class/gpio/gpio$2/direction ;
exit ;;
*) echo -e "Invalid operation $1. Try cmd --help\007" ; exit 1 ;;
esac
--Code End--
Maybe someone else may find this useful.
Ken
Mala Dies
Apr 7, 2020, 6:20:18 PM4/7/20
to BeagleBoard
Hello KenUnix,
Seth here. Do you want me to still work on the C++ code or are you satisfied w/ the shell script you are working on currently?
Seth
P.S. I found my book, ideas, and everything is on chapter six w/ source already done for specific ideas. I would probably need to change some source, too. Let a brother know.
jonnymo
Apr 7, 2020, 6:28:31 PM4/7/20
to Beagle Board
Is this what you are referring to?
Jon
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KenUnix
Apr 7, 2020, 6:30:54 PM4/7/20
to BeagleBoard
Seth,
Yes I am still interested. brb.
Try out that script. It's kind of neat. Let me know what you think.
After downloading it to a file chmod 755 filename
It's actually useful cmd is the name you give the
file. In my case I called it relay
cmd state 115
cmd on 20
cmd off 20
cmd label 7
cmd out 112
cmd --help
I just finished another script that exercises the relays.
See you on the Kiwi flip side...
KenUnix
KenUnix
Apr 7, 2020, 6:41:06 PM4/7/20
to BeagleBoard
Jon,
Thanks I will look at them.
Did you see that script I uploaded? Give it a try.
Ken
jonnymo
Apr 7, 2020, 8:47:57 PM4/7/20
to Beagle Board
Ken,
Sorry I do not have a Relay board, but I have done the shell scripting thing before.
Are you using a BB Black?
I am curious as to what Seth/Mala comes up with though.
Cheers,
Jon
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Shabaz Yousaf
Apr 7, 2020, 8:58:00 PM4/7/20
to Beagle Board
There's also a semi-Arduino-like C library I partially worked on described here:
.. that was tested in the latter half of 2019, on BBB and PocketBeagle. Turning a pin on/off in C is like this:
Setup:
#include <iobb.h>
iolib_init(); // initialize the library
iolib_setdir(8, 12, DigitalOut); // set the pin as an output
And then controlling a pin connected to a relay board or whatever:
pin_high(8, 12);
pin_low(8,12);
where the '8' represents the connector P8, and the '12' represents pin 12 on that connector.
It's not pretty code, it's quite ropey, but it worked in the limited tests I've used it for, and it supports I2C and SPI too. Plus it's fast, toggle speed is > 2MHz.
I started trying to port it to BB-AI, but have put it on pause for now, so many register differences : (
From: beagl...@googlegroups.com <beagl...@googlegroups.com> on behalf of jonnymo <jonn...@gmail.com>
Sent: 08 April 2020 01:47
To: Beagle Board <beagl...@googlegroups.com>
Subject: Re: [beagleboard] Re: 4 Relay relay Cape 'c' code
Sent: 08 April 2020 01:47
To: Beagle Board <beagl...@googlegroups.com>
Subject: Re: [beagleboard] Re: 4 Relay relay Cape 'c' code
To view this discussion on the web visit
https://groups.google.com/d/msgid/beagleboard/CAG99bkrt_RnDAm%3Drbj3kjs3SEqZXKmeCSXF8AQi9TXDkptERQw%40mail.gmail.com.
KenUnix
Apr 7, 2020, 9:01:17 PM4/7/20
to BeagleBoard
Jon,
I'll let Seth know.
Regarding me yes I have a BBB with a relay cape running Debian 10.3 IoT 3-26-2020
And a 4 port usb-2 powered hub and a .Realtek RTL8188EUS USB WiFi adapter.
I always like tp glance at code. You never know
when you will find something interesting. That's
how it was for me when I first started using Unix
back in 1974.
Ken
Mala Dies
Apr 8, 2020, 5:42:29 PM4/8/20
to BeagleBoard
Hello jonnymo,
Seth here. The book exploringBB has some nice source for C++ workings w/ it geared to, on Chapter 6, GPIO and other peripherals.
Seth
P.S. See here: https://github.com/derekmolloy/exploringBB/tree/version2/chp06. Although this was from two years ago, I am sure if we work on it, minor improvements or some similar changes might be all that is needed. Who knows?
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Mala Dies
Apr 8, 2020, 5:46:00 PM4/8/20
to BeagleBoard
Hello shabaz,
Seth here. I have been trying to find time to use this library. If it works on the new image, I will do my work to make time to use it.
Seth
P.S. I saw this library a long time ago. I have been staying patient in case there were some other people that were to update it. Are you familiar w/ MRAA and UPM libraries from Eclipse?
On Tue, Apr 7, 2020 at 3:41 PM KenUnix <ken.u...@gmail.com> wrote:
--Jon,
Thanks I will look at them.
Did you see that script I uploaded? Give it a try.
Ken
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On Tue, Apr 7, 2020 at 3:41 PM KenUnix <ken.u...@gmail.com> wrote:
--Jon,
Thanks I will look at them.
Did you see that script I uploaded? Give it a try.
Ken
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Mala Dies
Apr 8, 2020, 5:47:43 PM4/8/20
to BeagleBoard
Hello,
I am thankful that you updated me yesterday. I am waiting to try out the iobb library from shabaz soon. If you test it, let a brother know how it works out.
Seth
jonnymo
Apr 8, 2020, 6:00:58 PM4/8/20
to Beagle Board
Mala,
Yeah, I have 3 variations of Molloy's books and I do find them quite nice. His code more up to date than the shabaz code, so I would prefer that.
The other option is the AdaFruit BBIO Python code, which I believe Molloy uses.
Regardless, its best to just understand how the underline system is working and how to make calls to the GPIO pins and then go your own route.
Jon
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Shabaz Yousaf
Apr 8, 2020, 6:54:46 PM4/8/20
to Beagle Board
The Derek Molloy code (at least from the link below from Seth) uses Linux system 'sysfs' to perform the low-level GPIO, so it is far slower than the method I ended up using (which directly maps and modifies the registers). Despite it not being a microcontroller,
I still sometimes want that high speed. For instance, I used my library to make an FPGA programmer with the BBB. It runs fast. Also, I already had a BBB book - didn't really fancy buying another book, I don't see the point when I can write a simple-to-use
GPIO library and document it as well as a book might.
It depends on what's wanted. I prefer (naturally, otherwise I would not have written it : ) my method, primarily for the high speed and Arduino-like simplicity. The disadvantages of this method are that it's not as portable (as evidenced by the time taken to
port to BB-AI : ( - due to having to go down to register level, so it is restricted to BBB and PocketBeagle so far. Another disadvantage is that the code is poor, it deserves a re-write from scratch. I'd hoped someone would have written a better library over
the years so it would not be needed, but fast-forward five years, in 2019 I still
couldn't find a usable fast library, so (for my purposes) I had to ressurect it and re-test it - because of non-backward-compatible changes in the BBB Linux image that had occurred over the years.
Having said all that, if all that is needed is to control relays, today I'd also consider to do it with Python, because that's fast enough. No point using a fast library unless you plan to use it for future things that may need the higher speed.
Also, nothing wrong perhaps with doing it in a bash script, it's just not something I prefer (I'm not super-familiar with shell scripts, so I do the bare minimum in such scripts).
For the past few years I've also used the Pi (with the wiringPi C library, which is also fast and Arduino-like). I built my own relay board for it. I wrote code for it in C (usable with Python of course) to be able to control relays from Python or from bash
scripts etc.
The only suggestions I have based on that experience, is if you're going to switch multiple relays on or off simultaneously, then it's 'friendlier' electrically to have a few millisecond pause between each. I ended up incorporating that in my code, i.e. for
simultaneous control it would automatically stagger by a few milliseconds multiple relays switching on to make it just a perceived simultaneous time.
From: beagl...@googlegroups.com <beagl...@googlegroups.com> on behalf of jonnymo <jonn...@gmail.com>
Sent: 08 April 2020 23:00
To: Beagle Board <beagl...@googlegroups.com>
Subject: Re: [beagleboard] Re: 4 Relay relay Cape 'c' code
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Mala Dies
Apr 8, 2020, 7:03:24 PM4/8/20
to BeagleBoard
Hey Sir,
Yep. I will test out this C source soon. I guess you are right. It boils down to what I want. I mean, if you wanted it and I did not, I guess I would be wasting my time using it. W/ that typed out, I would like to use your library.
...
Should I put where I got the library in my source if used?
Seth
P.S. For instance, should I reference each of your names from the github page or can I just put https://github.com/shabaz123/iobb in the source?
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Shabaz Yousaf
Apr 8, 2020, 7:11:19 PM4/8/20
to BeagleBoard
Hi Seth,
Exactly that, it's just an option to consider or rule out, for this or a future project.
It's pretty open, only limits liability. It can be used in commercial or open source projects, and can be distributed in binary or source form, provided the text below is placed somewhere.
As far as I know, it was used in a product, and it was used for an academic paper:
| Copyright (c) 2015, Shabaz, VegetableAvenger | |
| All rights reserved. | |
| Redistribution and use in source and binary forms, with or without | |
| modification, are permitted provided that the following conditions are met: | |
| * Redistributions of source code must retain the above copyright notice, this | |
| list of conditions and the following disclaimer. | |
| * Redistributions in binary form must reproduce the above copyright notice, | |
| this list of conditions and the following disclaimer in the documentation | |
| and/or other materials provided with the distribution. | |
| * Neither the name of BBBIOlib, iobb, libiobb nor the names of its | |
| contributors may be used to endorse or promote products derived from | |
| this software without specific prior written permission. | |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE | |
| DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE | |
| FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR | |
| SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER | |
| CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, | |
| OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
From: beagl...@googlegroups.com <beagl...@googlegroups.com> on behalf of Mala Dies <fun...@gmail.com>
Sent: 09 April 2020 00:03
To: BeagleBoard <beagl...@googlegroups.com>
Sent: 09 April 2020 00:03
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KenUnix
Apr 8, 2020, 7:32:05 PM4/8/20
to BeagleBoard
Snabaz,
If I want to simply control a relay 1. Tthis simple 'c' would work
--Start Code--
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
int main()
{
int fd = open( "/sys/class/gpio/gpio20/value", O_RDWR | O_CLOEXEC ); // Relay 1
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
int main()
{
int fd = open( "/sys/class/gpio/gpio20/value", O_RDWR | O_CLOEXEC ); // Relay 1
if( fd < 0 ) {
fprintf( stderr, "open: %m\n" );
exit(1);
}
char c = '0'; // 0 = off, 1 == on
write( fd, &c, 1 );
close( fd );
return 0;
}
--End Code--
Being away from 'c' for some time I would like to add 2
command line arguments. Example command 1 20
where as command 1 30 would fail.
1. 0 or 1 for on or off
2. gpio # 20, 7,112 and 115. And validate input was 20, 7, 112 or 115.
If you want more control on, off, state, label this bash script will do it
--Start Code--
--End Code--
Feel free to use the bash script. If you down load it don't forget
to chmod 755 filename that way you can execute by ./filename
Ken
Shabaz Yousaf
Apr 8, 2020, 7:46:39 PM4/8/20
to BeagleBoard
Hi Ken,
That code looks like it would work. If you want to have command line arguments, the
int main(void)
gets replaced by something like:
int main(int argc, char** argv)
and then you can inspect the argc value to see the number of arguments, and the text for each argument will be pointed to by the array of pointers argv.
However, personally I find that once you start wanting more than the most basic command line, then it's sometimes better to bite the bullet and use a command line library, rather than manually try to read and parse the arguments.
An easy-to-use one is called argp. Others may have different favorites.
I'm curious what the reason is to use C though, if the bash script works. Python is preferable to C sometimes too.
Depending on how much lily-guilding is needed, another feature could be some mapping between friendly names and GPIO names, in (say) a JSON file.
So, then the command to switch on one relay could be: relay mylamp 1
That's incidentally easier in Python, because it's easy to read config files and write them, and so on. But if you've already got working code, it can be better to use that sometimes too.
From: beagl...@googlegroups.com <beagl...@googlegroups.com> on behalf of KenUnix <ken.un...@gmail.com>
Sent: 09 April 2020 00:32
To: BeagleBoard <beagl...@googlegroups.com>
Sent: 09 April 2020 00:32
To: BeagleBoard <beagl...@googlegroups.com>
Subject: Re: [beagleboard] Re: 4 Relay relay Cape 'c' code
--
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KenUnix
Apr 8, 2020, 8:09:52 PM4/8/20
to BeagleBoard
shabaz,
To be honest during my working carrier I only used 'C', Basic, Fortran, Cobol and bash.
At this point in my life I don't really want to learn something new like Perl or Python unless
I have to. My eyes are not what they used to be. Also, if you write in pure 'C' isn't it more
portable without the need for libraries which some day may not be there. Perhaps some
day I will try and learn Python.
Hardware I worked on was DEC PDP-11/70's, Tandem Non-Stop, Motorola Unix on
Mc68010 machines, HP 9000 servers and various versions of Linux, Ubuntu, Debian,
Linux Mint LMDE4 and Linux Light..
I have gotten to the point of making portable scripts to install all the required software
on my Linux platforms which I run under Oracle VirtualBox. They install the usual
applications, development tools and local code. They are written in bash.
My memory is "swelled" with all this stuff.
Ken
Shabaz Yousaf
Apr 8, 2020, 8:20:27 PM4/8/20
to beagl...@googlegroups.com
Hi Ken,
I can understand, that makes sense.
Also, that’s quite a variety of interesting machines.
Sent from Mail for Windows 10
From: KenUnix
Sent: 09 April 2020 01:10
To: BeagleBoard
Subject: Re: [beagleboard] Re: 4 Relay relay Cape 'c' code
shabaz,
--
For more options, visit http://beagleboard.org/discuss
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KenUnix
Apr 8, 2020, 9:22:18 PM4/8/20
to BeagleBoard
shabaz,
All that old hardware is gone now.. You or other users may find
the attached information useful. No copyright. Free to use.
If interested send me some feedback.
Thanks,
Ken
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