I get a pack not defined error when using i2c API

[jkroso]

No description provided.

[AIxer]

me too

[abassign]

Me too I2c (but I also see Wave) gives the same problem. Observing the code, the pack () function seems to act as a serializer that brings the character "I" and the flag 0 to become a vector which is then scanned by a Pi.jl function
Unfortunately I can not understand anything else, it would be useful to be able to solve the problem as JUlia lends itself very well to build RT systems in Raspberry environments.

[abassign]

The only library worthy of being used to interface to the Raspberry I / O does not work for the I2C protocol, fundamental protocol, it causes the error, right in the opening of I2C, when I try to open I2C I get this message:

i2 = PiGPIO.i2c_open (pi, 1,0x1e)
ERROR: UndefVarError: pack not defined

I noticed that the program converts the corresponding python code reported in this link.

the corresponding python code can be found here:

def i2c_open(self, i2c_bus, i2c_address, i2c_flags=0):
      """
      Returns a handle (>=0) for the device at the I2C bus address.

          i2c_bus:= >=0.
      i2c_address:= 0-0x7F.
        i2c_flags:= 0, no flags are currently defined.

      Normally you would only use the [*i2c_**] functions if
      you are or will be connecting to the Pi over a network.  If
      you will always run on the local Pi use the standard SMBus
      module instead.

      Physically buses 0 and 1 are available on the Pi.  Higher
      numbered buses will be available if a kernel supported bus
      multiplexor is being used.

      For the SMBus commands the low level transactions are shown
      at the end of the function description.  The following
      abbreviations are used:

      . .
      S     (1 bit) : Start bit
      P     (1 bit) : Stop bit
      Rd/Wr (1 bit) : Read/Write bit. Rd equals 1, Wr equals 0.
      A, NA (1 bit) : Accept and not accept bit. 
      Addr  (7 bits): I2C 7 bit address.
      reg   (8 bits): Command byte, which often selects a register.
      Data  (8 bits): A data byte.
      Count (8 bits): A byte defining the length of a block operation.

      [..]: Data sent by the device.
      . .

      ...
      h = pi.i2c_open(1, 0x53) # open device at address 0x53 on bus 1
      ...
      """
      # I p1 i2c_bus
      # I p2 i2c_addr
      # I p3 4
      ## extension ##
      # I i2c_flags
      extents = [struct.pack("I", i2c_flags)]
      return _u2i(_pigpio_command_ext(
         self.sl, _PI_CMD_I2CO, i2c_bus, i2c_address, 4, extents))

i2c_flags = 0
extents = [struct.pack("I", i2c_flags)]

convert in:
[b'\x00\x00\x00\x00']

The struct-pack is described in this link

function i2c_open(self::Pi, i2c_bus, i2c_address, i2c_flags=0)
    # I p1 i2c_bus
    # I p2 i2c_addr
    # I p3 4
    ## extension ##
    # I i2c_flags
    extents = [pack("I", i2c_flags)]
    return _u2i(_pigpio_command_ext(
        self.sl, _PI_CMD_I2CO, i2c_bus, i2c_address, 4, extents))
end

In python is:

extents = [struct.pack("I", i2c_flags)]
      return _u2i(_pigpio_command_ext(
         self.sl, _PI_CMD_I2CO, i2c_bus, i2c_address, 4, extents))

In julia In Julia there is an equivalent function a struct.pack(,Value)
the name is MsgPack

Now this is the problem, I would be delighted if the authors resolved it to allow the use of the I2C protocol.

[Alexander-Barth]

In the branch i2c, I have replaced the calls to pack("I",...).

master...i2c

Maybe somebody wants to test it. If it does not work, knowing the python message send to the daemon, by adding a
print(ext) to the python code would be tremendously helpful :-)