Problem transmitting doubles from Arduino to Python

[2447SN]

Hi great library, it is very useful, thank you.
I am having trouble sending some data from Arduino to Python. I have it working nicely if my data type is a single byte but if I change to an int or a double the python library isn't behaving as I would expect. Here is an example.
In Arduino I transmit two doubles each with a size of 8 bytes

double var1 = 1;
double var2 = 2;
baseStationSerial.txBuff[0]= var1;
baseStationSerial.txBuff[1]= var2;
baseStationSerial.sendData(16);

In python I read the received bytes into an array and print the array.

response = bytearray()
for index in range(model.link.bytesRead):
response.append(model.link.rxBuff[index])
print(response)

This is what I get in the array
bytearray(b'\x01\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')

This is what I would expect
bytearray(b'\x01\x00\x00\x00\x00\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00')

Any ideas?

Thanks

[PowerBroker2]

Can you post your entire Python and Arduino programs along with a description of what your project is supposed to do?

[PowerBroker2]

Note that the contents of the txBuff should be byte-sized and no larger. If you want to stuff larger values into txBuff, you will have to use a combination of msb(val), lsb(val), and byte_val(val, pos) to break down your value's pieces into individual bytes to be then stuffed into the txBuff.

You can also use Python's struct package to do byte stuffing as well (as found in the Python application Thunder Viewer):

    def stuff_float(self, val, start_pos):
        '''
        Description:
        ------------
        Insert a 32-bit floating point value into the (pySerialTransfer) TX
        buffer starting at the specified index
        
        :param val:       float - value to be inserted into TX buffer
        :param start_pos: int   - index of TX buffer where the first byte of
                                  the float is to be stored in
        
        :return start_pos: int - index of the last byte of the float in the TX
                                 buffer + 1
        '''
        
        val_bytes = struct.pack('f', val)
        
        self.transfer.txBuff[start_pos] = val_bytes[0]
        start_pos += 1
        self.transfer.txBuff[start_pos] = val_bytes[1]
        start_pos += 1
        self.transfer.txBuff[start_pos] = val_bytes[2]
        start_pos += 1
        self.transfer.txBuff[start_pos] = val_bytes[3]
        start_pos += 1
        
        return start_pos

[2447SN]

Ok thanks I think that answers my question.

[PowerBroker2]

No problem! Let me know if you still have questions