Serial1 and USBSerial1 on v.6.0 firmware

Hello All,

I used the Window firmware upgraders to flash v5.3 and then flash v.6.0.

But now when I use USBSerial1 there appears to be no temporary buffer for any data that is printed before I open a terminal (Putty) in windows. I.e anything I print in my setup() is missed, only commands executed in loop() will appear. Is this normal for v6.0 and is there a way to turn this on?

Secondly My USB driver can see both COMs (3&7 for me) and while USBSerial1 works on COM7 I cannot use Serial1 on COM3.

Can anyone help me with ways of debugging this? or confirm that this should be working?

I’ve uninstalled the driver, rebooted the computer and re-flashed the program but I’m still not able to use Serial1.
My operating system is windows 10.

Thankyou very much.


You won’t see Serial1 on your PC unless you use an external RX/TX-USB converter.
The original USB serial port is Serial not Serial1

And I’m pretty sure the buffering would need to happen on your PC since there is no handshake that would hold the transmission back from sending the data out (any other way this would block your code once the buffer got filled but not read).

Thanks for the quick response.

My goodness that was a brain fade with Serial1. I can confirm that Serial works just fine.

I’ll have a look at the computer side of things for the buffer issue. I guess my computer must be disregarding the COM port buffer when no program has a connection to it.

Appreciate your help.


1 Like