Hi,
I'm using an Arduino Pro Mini 328 16MHz / 5V together with a generic PL230X USB ttl serial converter.
Until today I haven't experienced any issue with this combination. Now whenever I try to upload, I get this error:
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0xa6
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x79
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x73
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x74
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x65
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x6d
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x20
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x53
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x74
While my code starts with:
void setup() {
Serial.begin(19200);
pinMode(SERIAL_WREN_PIN, OUTPUT);
digitalWrite(SERIAL_WREN_PIN, LOW);
Serial.println("System Started");
So it seems on this unit, the code starts before avrdude can synchronise with the bootloader. (The responses are ASCII for the println command 
I've tried different programmers, units, code, with or without external power supplies and about thirty times with manual resetting the unit. Also when trying to use avrdude directly, I can only get to this error. I have multiple units running this code and I've never had to place a time delay in front of my setup code.
Is there anyone who might have a suggestion how to overcome this issue and/or why this happens in the first place?
Thanks,
Teun
tkteun@tk-2540p:~$ avrdude -v -v -v -v -pm328p -b19200 -cSTK500v1 -P/dev/ttyUSB0 -e
avrdude: Version 6.0.1, compiled on Sep 20 2013 at 18:33:32
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2009 Joerg Wunsch
System wide configuration file is "/etc/avrdude.conf"
User configuration file is "/home/tkteun/.avrduderc"
User configuration file does not exist or is not a regular file, skipping
Using Port : /dev/ttyUSB0
Using Programmer : STK500v1
Overriding Baud Rate : 19200
avrdude: Send: 0 [30] [20]
avrdude: Send: 0 [30] [20]
avrdude: Send: 0 [30] [20]
avrdude: Recv: . [a6]
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0xa6
avrdude: Send: 0 [30] [20]
avrdude: Recv: y [79]
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x79
avrdude: Send: 0 [30] [20]
avrdude: Recv: s [73]
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x73
avrdude: Send: 0 [30] [20]
avrdude: Recv: t [74]
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x74
avrdude: Send: 0 [30] [20]
avrdude: Recv: e [65]
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x65
avrdude: Send: 0 [30] [20]
avrdude: Recv: m [6d]
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x6d
avrdude: Send: 0 [30] [20]
avrdude: Recv: [20]
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x20
avrdude: Send: 0 [30] [20]
avrdude: Recv: S [53]
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x53
avrdude: Send: 0 [30] [20]
avrdude: Recv: t [74]
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x74
avrdude: Send: 0 [30] [20]
avrdude: Recv: a [61]
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x61
avrdude done. Thank you.
I probably have no idea what it actually is, but have you tried holding reset to upload?
Yes, that's what I meant by manually resetting: Instead of using the DTR lead, I hold the reset button until Arduino is finally finished compiling and starting the upload.
(why must it always fully compile the project?)
What pin is SERIAL_WREN_PIN?
Ahh, yes, I meant to take that out for clarity.
It's a pin which normally is connected to the /RE and DE pins of a MAX485 tranceiver.
I normally leave it connected to the RX and TX pins while programming, but I've disconnected it while troubleshooting this module.