Hi,
First post here, but I've been playing for some time.
I acquired a few Arduino Uno from Ebay. I installed some simple code to output some text on the RS232 line, that can be monitored by the Serial Monitor. I've attached the code. It also flashes a led on Pin 4, I had to get away from using the pin 13 stardard, as I could not tell if the bootloader was flashing the led or not.
So my question is;
Does the Arduino not recognise that it has a serial port installed once the USB is removed? Why? Well after the upload, the Tx led lights up nicely and and the text appears in the serial monitor. Unplug the USB, and no more flashing Tx. Plug it back in, and no Tx lights up.
I thought I had acquired a Uno with amnesia as mentioned on the sparkfun website, and even programmed the bootloader on it. This didn't help, but it did make the Pin13 led flash differently, so it appears that a different boot loader has been installed.
Anyway I digress, is this just the way the standard serial/USB port works? I've searched high and low for an answer but its just not getting answered.
Cheers
Col
Arduino_PH_Probe_Emulator.ino (3.39 KB)