Byte sent as Binary - Serial

I am attempting to read bytes sent from Arduino Uno using Serial.Write (Documents say this sends data as binary)
I have confirmed via Realterm that each byte is sent as 1 8bit binary group (0 to 255 = 00000000 to 11111111)

In the Serial DataAvailable event I have

Dim m As MemoryBlock = frmMain.Serial1.ReadAll(Encodings.WindowsANSI)
frmMain.txtIncoming.Text = frmMain.txtIncoming.Text + str(m.byte(0))

This gives me 0-63 but then restarts at 0. I have confirmed (via Realterm) that the arduino sketch is indeed sending all bytes from 0-255 and viewing the memoryblock in xojo debug confirms there is only one byte…

So what am I missing? Obviously there is something I don’t understand.
I have tried multiple ‘Encodings’ to no avail.

Any help would be appreciated.

  • Windows 10 64Bit -

I believe that the default protocol settings are 7N1. Make sure you’re setting the Serial protocol to Bits=8, Parity=0, StopBits=1. Otherwise, the 8th bit of each byte is dropped and used as the parity bit.

Or, UUENCODE or BASE64ENCODE the binary so that it is compatible with 7E1 or 7O1 transmission.

I never thought that I’d need THAT particular knowledge ever again :S

Tim: Thanks for the reply, yes my settings are 115200 8-N-1 (on both ends)

Then that is odd as 0-255 are now mostly good (except for the reserved signal bits below 32 ASCII).

Are you certain that it’s on the PC end and not the Arduino end? How are you connecting serially to the Arduino?

Ya, the data spits out fine using Realterm console… (connecting via usb which converts to com port) I get the full range of 0-255 monitoring with binary or hex.

Watching the memoryblock it gets to 3F and then starts over


What I need is to be able to receive all bytes 0-255

Here is the Arduino Test Code if you are interested…

byte mybyte = 0;
byte trash;

void setup() {
  // start serial port at 115200 bps default 8-n-1
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  //clear serial
  while (Serial.available() > 0) {
    trash =;  
void loop() { 
  //send byte 
  //increment counter
  if (mybyte == 255) {
    mybyte = 0;
  //wait 1s

Ah - I misunderstood what you were trying to accomplish - it’s not the value of the bytes, but the number of them in the loop. Is that correct? So what you are doing is trying to send byte values 0 to 255 over the link In a loop?

Thanks for your initial post Tim, I went back to ensure that I was Indeed setting the serial port correctly. I disabled MY dropdowns that allowed the user to set the port settings, and commented them out.

I set the port manually via the xojo IDE and it “magically” started working correctly.

Obviously I have something messed up with my listindex properties …

Don’t I feel like a horses patoot.