Can't unpload to Mini Pro

Hi all,

Used Nick Gammon's chip programmer with the UNO-R3 as ISP to burn bootloader on Pro Mini (with ATmega 328P); worked fine result ok.

But can't upload sketch to Pro Mini through USB2SERIAL (worked before burning bootloader and still works with other Pro Mini) and I get the comment:

avrdude: stk500_getsync(): not in sync: resp=0x00

Can anyone tell me what this means? What can I do to make it work again?

The basic issue is that there is no automatic reset of the Mini Pro when the serial line becomes active.

Here is the process that I use:

  1. Start the compile/download cycle
  2. At some point the 'Rx' LED on the MiniPro will flash.
  3. Press the reset button when this happens.
  4. The bootloader will take over on reset and allow the download to be executed.

It can be a bit tricky, but like most of these things the timing will comm with practice :slight_smile:

An alternative is to modify the Pro Mini woith a capacitor (from memory) that reset the serial line. You can search for this using google.