Just another sketch upload failure ...

Using Arduino IDE 1.x
1

My configuration has a raspberry pi 3 (ubuntu mate 1.16.2) with two arduino nano connected via USB.

When the two arduinos are unplugged from their circuits, upload works fine. When they are plugged, upload fails with

Arduino: 1.8.5 (Linux), Board: "Arduino Nano, ATmega328P"

Sketch uses 5668 bytes (18%) of program storage space. Maximum is 30720 bytes.
Global variables use 618 bytes (30%) of dynamic memory, leaving 1430 bytes for local variables. Maximum is 2048 bytes.
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
...

Both boards have TX, RX and RST pins not connected in the circuit.

Almost every I/O pin is used, Each board loads a different sketch and it is connected to the circuitry with a different schematic.

When the system is running and boards are plugged, both boards work properly.

Any idea?

Thanks

2

What is the power situation? Either of these?

a) the circuitry is powered from the Arduino Nanos, and they or the RPi is overloaded?
b) you have external power supplies, extra volts (or noise) upsetting things?

3

Sounds like you've connected something that uses or puts a load on pins 0, 1, or reset. Those pins are needed for uploading - you can't have anything that puts a load on those pins if you want to upload while the rest of your project is connected.

4