[PD] Sensors GPIO Raspberry Pi Pd

Martin Peach martin.peach at sympatico.ca
Sat Apr 20 23:17:17 CEST 2013


Oh sorry, it segfaults if you don't pass an argument at startup. (1 if 
it's already initialized, 0 if not)
The line begining "if (argc > 0)" should say "if (argc > 1)".

Martin


On 2013-04-20 13:30, Martin Peach wrote:
> Well that looks a total mess...
>
> I did "sudo apt-get install i2c-dev" before all this, as well as all the
> things in http://www.instructables.com/id/Raspberry-Pi-I2C-Python/#step1
> except I didn't use any python.
> The segfaults might be because you are asking for more than 32 bytes in
> a read, or something wrong in the code, the listing below looks like it
> goes wrong right at the beginning.
>
>
> Martin
>
> On 2013-04-19 17:37, Julian Brooks wrote:
>> As I'm new to all this C stuff I just had a look inside the 'hello' file
>> and there's a few bits in there which may be of interest:
>> ^@D6T_checkPEC says 0x%02X
>> (which I think is ok from looking at the code?)
>> then it all goes wrong
>> ^@^@^@Unable to create socket (%d)
>> ^@^@^@>> %s <<
>> ^@^@^@127.0.0.1 <http://127.0.0.1>^@^@^@Unable to make address from %s
>> ^@%s: initialized:%d
>> ^@/dev/i2c-0^@^@Failed to open the bus. (%d)
>> ^@^@^@Failed to acquire bus access and/or talk to slave. (%d)
>> ^@^@^@^@Write failed (%d)
>> ^@^@Read failed (%d)
>> ^@^@^@%d ^@<0x%02X>
>> ^@^@^@d6t8l^@^@^@ %d^@
>> ^@^@^@sendto error (%d)
>>
>> BTW - I've removed libi2c-dev again and will leave it that way for now.
>>
>> Going to stop now but will be back tomorrow.
>>
>> Cheers,
>>
>> Julian
>>
>>
>>
>>
>>
>> On 19 April 2013 22:07, Julian Brooks <jbeezez at gmail.com
>> <mailto:jbeezez at gmail.com>> wrote:
>>
>>     Edited your original file and all I changed was the ip address to
>>     127.0.0.1 and still seg fault (double checked /etc/hosts too).
>>
>>     Also tried reinstalling libi2c-dev and then running 'hello' - same.
>>
>>
>>     On 19 April 2013 21:54, Julian Brooks <jbeezez at gmail.com
>>     <mailto:jbeezez at gmail.com>> wrote:
>>
>>         hmmm - both files:
>>         ./hello-2
>>         Segmentation fault
>>
>>         Try again...
>>
>>
>>
>>         On 19 April 2013 21:51, Julian Brooks <jbeezez at gmail.com
>>         <mailto:jbeezez at gmail.com>> wrote:
>>
>>             Ok -found I had to remove 'libi2c-dev'.
>>
>>             Then builds.
>>
>>             More soon...
>>
>>
>>             On 19 April 2013 21:28, Julian Brooks <jbeezez at gmail.com
>>             <mailto:jbeezez at gmail.com>> wrote:
>>
>>                 Hey Martin,
>>
>>                 When I try to compile hello.c I get:
>>                 gcc -o hello hello.c
>>                 In file included from hello.c:8:0:
>>                 /usr/include/linux/i2c-dev.h:38:8: error: redefinition
>>                 of 'struct i2c_msg'
>>                 /usr/include/linux/i2c.h:67:8: note: originally
>> defined here
>>                 /usr/include/linux/i2c-dev.h:90:7: error: redefinition
>>                 of 'union i2c_smbus_data'
>>                 /usr/include/linux/i2c.h:125:7: note: originally defined
>>                 here
>>
>>                 Dunno if this is at all relevant but maybe this is a
>>                 good time to say I have a rev1 RPi so I'm on i2c 0 not 1.
>>                 The Pi install is very up to date though, including
>>                 recent runs of hexxeh's 'rpi-update' tool so all the
>>                 system's fresh.
>>
>>                 I did attempt to change the number of bytes to be read
>>                 which perhaps would explain why the .h file's are
>>                 complaining but I don't understand it for your version
>>                 which is 'as-is'?
>>
>>                 In fact why don't I attach the notes I've made of the
>>                 changes to the c file you sent.  Was vaguely hoping I
>>                 might be able to say 'ta da' but have fallen at the 1st
>>                 fence:( bugger.
>>
>>                 Julian
>>
>>
>>
>>
>>
>>                 On 19 April 2013 19:51, Julian Brooks <jbeezez at gmail.com
>>                 <mailto:jbeezez at gmail.com>> wrote:
>>
>>                     Hi Martin,
>>
>>                     Meant to add re setting baud rate:
>>                     I've been making use of the gpio utility that comes
>>                     with wiringPi
>>
>> https://projects.drogon.net/raspberry-pi/wiringpi/the-gpio-utility/
>>                     Very handy for getting a quick visualisation of the
>>                     current state of all the pins and also easy-access
>>                     to setting the baud rate too (amongst other stuff).
>>
>>                     Julian
>>
>>
>>                     On 19 April 2013 14:36, Martin Peach
>>                     <martin.peach at sympatico.ca
>>                     <mailto:martin.peach at sympatico.ca>> wrote:
>>
>>                         Hi Julian,
>>                         Yes I've been messing with coding it in c on the
>>                         pi and sending the data to a [netreceive] in a
>>                         Pd patch on another machine. I'm attaching the
>>                         source code for the pi part and the Pd patch.
>>                         The code can be compiled on the pi with
>>                         gcc -o hello hello.c
>>                         You need to set the IP address of the receiving
>>                         machine in the code (I have 192.168.2.15, it
>>                         could be 127.0.0.1 for the same machine).
>>                         I tried changing the baud rate with
>>                         sudo modprobe -r i2c_bcm2708
>>                         sudo modprobe i2c)bcn2708 baudrate=90000
>>                         but it works fine at the default 100000.
>>                         It seems that you only need to write the command
>>                         once, after that simply reading gets you another
>>                         packet. Using a combined write/read operation
>>                         only works half the time, as I also found on the
>>                         Arduino. All you need to do is write the 0x4C
>>                         command once, wait a millisecond or so and then
>>                         read it.
>>                         Another issue is that I tried this with the 8X1
>>                         sensor, not the 4X4 one, so the code reads 19
>>                         bytes (need to change the expected read size in
>>                         the code). The 4X4 sensor sends 35 bytes which
>>                         is 3 more than the i2c driver maximum, so you
>>                         may not get the last part of a packet.
>>                         I'll try it later with a 4X4 sensor to see what
>>                         happens.
>>
>>                         Martin
>>
>>
>>                         On 2013-04-19 07:01, Julian Brooks wrote:
>>
>>                             Hi Martin,
>>
>>                             Did you manage to make any progress with the
>>                             sensor on the Pi?
>>                             I also wanted to ask whether the output
>>                             we're receiving from i2cdump
>>                             makes any sense to you as it doesn't to us
>>                             currently?  Tried searching
>>                             around for possible info on the 'XX' & 'ff'
>>                             but drawing a blank here.
>>
>>                             Cheers,
>>
>>                             Julian
>>
>>
>>                             On 13 April 2013 01:11, Julian Brooks
>>                             <jbeezez at gmail.com <mailto:jbeezez at gmail.com>
>>                             <mailto:jbeezez at gmail.com
>>                             <mailto:jbeezez at gmail.com>>> wrote:
>>
>>                                  Hey all,
>>
>>                                  Some success finally:
>>
>>                                  Hurrah!!
>>
>>                                  The scl breakout pin on the pi proto
>>                             plate wasn't working properly.
>>
>>                                  When unscrewed halfway it works, when
>>                             fully screwed in it doesn't.
>>
>>                                  So - now got this:
>>
>>                                  i2cdetect -y 0
>>
>>                                  0 1 2 3 4 5 6 7 8 9 a b c d e f
>>
>>                                  00: -- -- -- -- -- -- -- 0a -- -- --
>> -- --
>>
>>                                  10: -- -- -- -- -- -- -- -- -- -- -- --
>>                             -- -- -- --
>>
>>                                  20: -- -- -- -- -- -- -- -- -- -- -- --
>>                             -- -- -- --
>>
>>                                  30: -- -- -- -- -- -- -- -- -- -- -- --
>>                             -- -- -- --
>>
>>                                  40: -- -- -- -- -- -- -- -- -- -- -- --
>>                             -- -- -- --
>>
>>                                  50: -- -- -- -- -- -- -- -- -- -- -- --
>>                             -- -- -- --
>>
>>                                  60: -- -- -- -- -- -- -- -- -- -- -- --
>>                             -- -- -- --
>>
>>                                  70: -- -- -- -- -- -- -- --
>>
>>                                  and
>>
>>                                  i2cdump -y 0 0xa
>>                                  No size specified (using byte-data
>> access)
>>
>>                                  Gives a whole host of stuff I don't yet
>>                             understand but I don't care
>>                                  currently as something is actually
>>                             happening.
>>
>>                                  Will figure out a way of saving the
>>                             console info (any hints
>>                                  anyone?)  as it gets badly mangled when
>>                             cutting and pasting  but
>>                                  basically something like this:
>>
>>                                  i2cdump -y 0 0xa
>>                                  No size specified (using byte-data
>> access)
>>                                        0  1  2  3  4  5  6  7  8  9  a
>>                               b  c  d  e
>>                                  f                      0123456789abcdef
>>                                  00: ff XX XX XX XX XX XX ff XX XX XX XX
>>                             ff ff ff XX    .XXXXXX.XXXX...X
>>                                  10: XX ff XX XX XX XX XX ff XX ff XX ff
>>                             XX XX ff XX    X.XXXXX.X.X.XX.X
>>                                  20: ff XX XX ff XX XX ff XX XX XX XX ff
>>                             XX XX XX ff    .XX.XX.XXXX.XXX.
>>                                  30: XX ff XX ff XX XX XX XX ff ff ff XX
>>                             XX XX XX XX    X.X.XXXX...XXXXX
>>                                  40: XX XX XX ff XX ff XX XX XX 64 XX XX
>>                             d5 XX XX ff    XXX.X.XXXdXX?XX.
>>                                  50: XX ff XX XX XX XX XX XX XX ff XX XX
>>                             ff XX XX XX    X.XXXXXXX.XX.XXX
>>                                  60: ff XX XX XX ff XX XX XX XX XX XX XX
>>                             XX ff XX XX    .XXX.XXXXXXXX.XX
>>                                  70: XX XX XX XX XX XX XX ff XX XX XX XX
>>                             XX XX XX XX    XXXXXXX.XXXXXXXX
>>                                  80: XX ff XX XX ff ff XX XX XX ff XX XX
>>                             XX XX XX XX    X.XX..XXX.XXXXXX
>>                                  90: XX XX ff XX XX ff XX ff XX ff ff XX
>>                             XX ff ff XX    XX.XX.X.X..XX..X
>>                                  a0: XX ff XX XX ff XX XX XX XX XX XX XX
>>                             XX XX ff XX    X.XX.XXXXXXXXX.X
>>                                  b0: XX XX ff XX XX XX ff XX XX ff XX XX
>>                             XX XX XX XX    XX.XXX.XX.XXXXXX
>>                                  c0: XX XX XX XX ff XX XX ff ff XX XX ff
>>                             ff XX XX XX    XXXX.XX..XX..XXX
>>                                  d0: XX XX XX XX XX ff XX ff XX XX XX XX
>>                             XX ff XX ff    XXXXX.X.XXXXX.X.
>>                                  e0: XX XX XX ff XX ff XX XX XX XX XX XX
>>                             XX XX ff XX    XXX.X.XXXXXXXX.X
>>                                  f0: ff XX ff ff XX XX XX XX XX XX XX XX
>>                             XX XX ff XX    .X..XXXXXXXXXX.X
>>
>>
>>                                  Progress at least.
>>
>>                                  Cheers,
>>
>>                                  Julian
>>
>>
>>
>>
>>
>>
>>
>>                                  On 12 April 2013 11:27, Julian Brooks
>>                             <jbeezez at gmail.com <mailto:jbeezez at gmail.com>
>>                                  <mailto:jbeezez at gmail.com
>>                             <mailto:jbeezez at gmail.com>>> wrote:
>>
>>                                      Message resent for thread archives
>>                             with smaller picture size.
>>
>>                                      Julian
>>
>>                                      ---------- Forwarded message
>> ----------
>>                                      From: *Julian Brooks*
>>                             <jbeezez at gmail.com
>>                             <mailto:jbeezez at gmail.com>
>>                             <mailto:jbeezez at gmail.com
>>                             <mailto:jbeezez at gmail.com>>>
>>                                      Date: 11 April 2013 19:24
>>                                      Subject: Re: [PD] Sensors GPIO
>>                             Raspberry Pi Pd
>>                                      To: Martin Peach
>>                             <martin.peach at sympatico.ca
>>                             <mailto:martin.peach at sympatico.ca>
>>                                      <mailto:martin.peach at __sympatico.ca
>>                             <mailto:martin.peach at sympatico.ca>>>
>>                                      Cc: PD List <pd-list at iem.at
>>                             <mailto:pd-list at iem.at>
>>                             <mailto:pd-list at iem.at
>> <mailto:pd-list at iem.at>>>
>>
>>
>>                                      Hey Martin / list,
>>
>>                                      Finally got all the stuff and ...
>>
>>                                      It’s not working!
>>
>>                                      We spent the day soldering cables
>>                             and connecting stuff up as per
>>                                      the Omron ‘App Note 01’ spec sheet.
>>
>>                                      Started off super-conservative
>>                             using the  I2C level converter
>>                                      (case 3 page 4)
>>
>> http://www.adafruit.com/__products/757#Blog/Flickr
>>
>> <http://www.adafruit.com/products/757#Blog/Flickr>
>>
>>                                      We tried resistors on both sides
>>                             (being super paranoid!) and
>>                                      then we took  the low (Pi) side
>>                             ones off.
>>
>>                                      We then moved on to case 2 page 3
>>                             of this same document…
>>
>>                                      At each stage we checked with
>>                             “I2Cdetect –Y 1” and nothing was
>>                                      visible.
>>
>>                                      The grid shows no attached devices
>>                             every time we run it.
>>
>>                                      We re-booted at every stage
>>                             following the various online
>>                                      tutorials/methods of setting up I2C
>>                             GPIO on the Pi (checked &
>>                                      double checked).
>>
>>
>>                                      As you can see we’re using a pi
>>                             protoplate:
>>
>>                             https://www.adafruit.com/__products/801
>>                             <https://www.adafruit.com/products/801>
>>
>>                                      In the photo I’ve attached the
>>                             cables are coded as follows:
>>
>>                                      Orange           GND
>>
>>                                      Yellow            5v
>>
>>                                      Blue                SCL
>>
>>                                      Green             SDA
>>
>>                                      The white is also 5v for the pull
>>                             up resistors.
>>
>>                                      The resistor values are 4.7k btw.
>>
>>                                      We have tested the cable that
>>                             terminates at the sensor and all
>>                                      that is OK.
>>
>>                                      I put a multimeter on the GND and
>>                             SDA solder points on the
>>                                      sensor itself and got 3.7v…
>>
>>                                      I put a multimeter on the GND and
>>                             SCL solder points on the
>>                                      sensor itself and got 0.0v…
>>
>>                                      Don’t know if this means anything
>>                             or could be useful to know!
>>
>>                                      Stuck and frustrated now but hey, 3
>>                             weeks ago I knew absolutely
>>                                      bugger all about any of this and
>>                             now I do (sort of).
>>
>>                                      I'm thinking we could do with the
>>                             most basic i2c sensor we can
>>                                      find as we have nothing to compare.
>>
>>                                      Tonight I'm going to d/l a fresh
>>                             raspbian and start from scratch
>>                                      to check that end.
>>
>>                                      Feel like if we can't get past the
>>                             'i2c-tools' tests we're
>>                                      screwed - never mind getting it in
>>                             and out of Pd.
>>
>>                                      Any thoughts/pointers/options from
>>                             anyone will be really
>>                                      appreciated?
>>
>>
>>                                      Cheers,
>>
>>
>>                                      Julian
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
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