sending strings with send_sysex about pyfirmata HOT 6 CLOSED

That is strange. What is the output?

I added this method to the tests and it passes...:

    def test_send_sysex_string(self):
        self.board.send_sysex(0x79, ["test"])
        sysex = (chr(0xF0), chr(0x79), 't', 'e', 's', 't', chr(0xF7))
        self.assert_serial(*sysex)

from pyfirmata.

I have tried the same code as @sunfffd and I'm also getting corrupt characters on my display.

@tino I have looked at your test and you are sending "0x79" to Firmata which is a firmware query.
"0x71" is the code for sending strings. I don't understand how your test can be accurate.

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I looked at the Firmata docs http://firmata.org/wiki/Protocol and according to the protocol spec, a string message must be 14-bits per char.
In pyfirmata.py, in the "send_sysex()" function, data is being send as 7-bits.
'Sysex data can be 7-bit bytes only. Consider using utils.to_two_bytes for bigger bytes.'

It seems like that could be the issues but I'm too noob with python to figure out how to use the "utils.to_two_bytes" function.

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I were able to figure it out :)
The chars need to be of 14-bits per char.

This can be send as per follows:
board.send_sysex(0x71, util.str_to_two_byte_iter("test message\0"))

If would be very nice if pyfirmata could do that for us.

def send_sysex(self, sysex_cmd, data=[]):
    """
    Sends a SysEx msg.

    :arg sysex_cmd: A sysex command byte
    :arg data: A list of 7-bit bytes of arbitrary data (bytes may be
        already converted to chr's)
    """
    #Convert strings to 14-bit chars. Also add a null terminator.
    if sysex_cmd == 0x71:
       data = str_to_two_byte_iter(data+"\0") 

    self.sp.write(chr(START_SYSEX))
    self.sp.write(chr(sysex_cmd))
    for byte in data:
        try:
            byte = chr(byte)
        except TypeError:
            pass # byte is already a chr
        except ValueError:
            raise ValueError('Sysex data can be 7-bit bytes only. '
                'Consider using utils.to_two_bytes for bigger bytes.')
        self.sp.write(byte)
    self.sp.write(chr(END_SYSEX))

Then we only need to call this:

self.board.send_sysex(0x71,"test")

This works fine and the string comes through as expected.

from pyfirmata.

Is this still a problem now that we are using byte arrays?

from pyfirmata.

Closing, as I can't move forward with this. Hopefully it's not a problem anymore!

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