Hardware Serial Upload during use question

All, Is it to be expected, that if I have a current stream into my Diecimilia on hardware 0/1, uploading a revised sketch will fail?


Yes, external circuitry driving (or even heavily loading) D0 or D1 will cause sketch upload to fail, these pins are used for communication with the bootloader by the USB interface via 1-10K resistors.

okay then, how will I be able to permatize my gps setup and still retain a serial buffer?

Thanks for helping a beginner.


Software Serial to the resue!


Also AFsoftserial is popular. Download from here


This does not lead to data lost? It was my understanding that only the hardware serial had a buffer, and that the software serial did not. If I have more than enough code to fill the time it takes to cycle back through for a read, will this not lead to data lost?

I want to be able to record several serial devices, and a buffer seems important to me.

Please, correct me where needed.


The hardware buffer on the serial I/O is only 1 byte. Also you will not be able to use several software serial input lines only one as it takes up all the processor time looking after the one.

The hardware buffer on the serial I/O is only 1 byte.

Yes, but it's serviced by an interrupt which fills a 128 byte buffer.