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I am trying to send packets of via bluetooth data that include 6 bytes read from a sensor and stored in a uint8_t array. Instead of sending over the data as numerical digital, I would like to send the ASCII character of each of the bytes. I am doing this to reduce the size of my data packets and make it easier to interpret the incoming data. 

uint8_t* temp = readBufferData(FIFO);

for (int i = 0; i < 6; i++)
{
    Serial.write(temp[i]);

}

Read buffer data returns a pointer to a uint8_t array read from a FIFO buffer. When I use Serial.print, I get the following output, which makes sense. 22163226094255 One question is, when I use Serial.print on a single character, is it transmitted a single byte, or is it actually sending the decimal digital of the number, anywhere from 1-3 bytes?

When I use the Serial.write, however, I get something like the following DÿÂ?ÁÏ?ÌÆ?Ûµ?˽?ÔÀ?п?ÃÕÓÑËÐTÿÀ?Ï3ÿÉ?¹4ÿÐ?Ê<ÿ½?µfÿ¼?ìNÿÐ?×Â?ÊÚ?׿?Å Also, these data display much more slowly on the screen, than normal.

How can I send each uint8_t value by sending over the corresponding ASCII character for serial transmission?

Thanks!

Alex K
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2 Answers2

2

You don't "convert" anything. A character is just a human representation of an 8-bit value.

Instead you just need to change what the compiler thinks the data represents (from a human perspective). The simplest way of doing that is to either cast the uint8_t values to be char values, or to write each one individually as a raw value.

The latter way:

myBluetoothSerial.write(myData[0]);
myBluetoothSerial.write(myData[1]);
myBluetoothSerial.write(myData[2]);
myBluetoothSerial.write(myData[3]);
myBluetoothSerial.write(myData[4]);
myBluetoothSerial.write(myData[5]);

Or, with a loop:

for (int i = 0; i < 6; i++) {
    myBluetoothSerial.write(myData[i]);
}

or using a built-in variant of write that does the loop for you:

myBluetoothSerial.write(myData, 6);
Majenko
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-1

Try changing Baud Rate. Most of the time garbage like this happens because of difference in baud rates of transmitter serial device and receiver serial device.

ARK
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