[arm-allstar] HamVoIP I/O support - What is Best Current Practice for implementing I/O?

[Doug Crompton]

Randy,

 Attached is the bcd_control.sh script. It controls 16 channels or 4 bits.
It has a strobe on a 5th bit that can be ignore if not needed. Here is and
example running it at the linux prompt -

./bcd_control.sh 2
Entered Channel 2
Channel 2 written to BCD - 0010

and just a portion of a 'gpio readall' showing the bits

 |   5 |  21 | GPIO.21 |  OUT | 0 | 29
 |   6 |  22 | GPIO.22 |  OUT | 1 | 31
 |  13|  23 | GPIO.23 |  OUT | 0 | 33
 |  19|  24 | GPIO.24 |  OUT | 0 | 35
 |  26|  25 | GPIO.25 |  OUT | 0 | 37

To control from Allstar here is one way to do it. Add to the functions
stanza, assumes the script is in /etc/asterisk/local. Make sure the script
is executable - chmod 750 bcd_control.sh. Run it manually as above to
confirm. You only need to enter functions for as many channels as you have.
In your case 3 bits or 8 channels. The script was not written for a
Motorola but it should work fine.

801=cmd,/etc/asterisk/local/bcd_control.sh 1
802=cmd,/etc/asterisk/local/bcd_control.sh 2
803=cmd,/etc/asterisk/local/bcd_control.sh 3
804=cmd,/etc/asterisk/local/bcd_control.sh 4
805=cmd,/etc/asterisk/local/bcd_control.sh 5
806=cmd,/etc/asterisk/local/bcd_control.sh 6
807=cmd,/etc/asterisk/local/bcd_control.sh 7
808=cmd,/etc/asterisk/local/bcd_control.sh 8
809=cmd,/etc/asterisk/local/bcd_control.sh 9
810=cmd,/etc/asterisk/local/bcd_control.sh 10
811=cmd,/etc/asterisk/local/bcd_control.sh 11
812=cmd,/etc/asterisk/local/bcd_control.sh 12

etc....

Another way to do this is use the autopatch in command mode. Then you just
need one line in rpt.conf  and a custom extensions.conf stanza. See the
howto on the hamvoip.org web page.

https://www.hamvoip.org/Allstar_extended_functions_using_autopatch.pdf

Again - VERY IMPORTANT! The Pi is 3V GPIO logic. Use diodes pointed towards
the radio on each line. You may possibly need to use pullups on the radio
side of the diode if the radio does not supply them. The radio lines
probably float high. If they do that won't be necessary.. You also need a
ground connection between the radio and the Pi. This could be Pi pin 37 or
any defined 0V pin.


*73 Doug*

*WA3DSP*

*http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*



On Fri, Jan 12, 2018 at 2:53 AM, "Randy Neals via arm-allstar" <
arm-allstar at hamvoip.org> wrote:

> Hi,
>
> What is the best current practice for implementing I/O on a Raspberry Pi to
> control external things.
> In this case, remote channel selection on a VHF remote base, a radio with 8
> channels and having external control lines.
>
> From looking through the list archives, I see references to using an
> Arduino Nano, and at an earlier time, using a USB I/O board from SparkFun,
> and of course using the lines on the RPi itself.
>
> Anticipated questions...
>
> Q. What Am I trying To Do?
> A. Control channel select lines on a VHF remote base station.
>
> Q. What format/How many lines?
> A. 3 logic control lines. The lines are normally pulled up to +5V by the
> radio.
>      BCD format with the lines having binary weighting of 4, 2, and 1
> respectively.
>      High = weighted value / Low = zero value.
>
> Q. What audio interface will I use?
> A. Simple USB, likely DMK URI. (But I could use a USB FOB, or other
> interface if there is one with I/O)
>
> Thanks,
> Randy
> W3RWN
> _______________________________________________
>
> arm-allstar mailing list
> arm-allstar at hamvoip.org
> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
>
> Visit the BBB and RPi2/3 web page - http://hamvoip.org
>
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