DTR/Auto reset isnt working.. need help where to start troubleshooting?

I have a custom board..

and I have been assembling them by using some DIY re-flow (solder paste, stencil, toaster oven)..

I have made two 'successful' boards (meaning they will take bootloader and accept sketches)

the 3rd one I am having a bit of trouble with..

looks to have taken the Optiloader bootloader I flashed to it (watched serial monitor from Optiloader sketch)..

I then pop out ATMEGA329 DIP chip in my Arduino Due 2009... and connect my custom board with pass through RX/TX lines... with the RESET line going to my DTR pin on my custom board..

this is how I have done my previous boards set-up..etc.

however.. I can NOT get a sketch to upload..

and I believe I might have a bridge somewhere?.. but not sure where to start looking I guess.

when I short the DTR pad to the GND pad next to it.. I do NOT see/get a reset/blink on my red light??

However if I short RESET pin to GND.. I get a quick blink.. (still not able to load sketches if i manually try to do that upon sketch uploading)..

my other boards seem to work fine.. connected and set-up same way...

what pins could bridge to be stopping my DTR pin form working?

heres a schematic.. but electrically it must be 'sound' as the other board 'work'..

Im just stumped as to where the bridge could be? figured I would start with some suggestions from the more experienced members here.

thanks

I then pop out ATMEGA329 DIP chip in my Arduino Due 2009... and connect my custom board with pass through RX/TX lines... with the RESET line going to my DTR pin on my custom board..

So does that mean the original DTR signal from the FTDI chip is passing through two series .1mfd caps (one on the 2009 board and one on your custom board) before it hits the reset pin on your custom board?, If so that could be the reason as there may not to a strong enough pulse to pull reset low enough on your custom board. Perhaps try jumpering out the cap on your custom board and try again. And of course you have a common ground wire installed between the two boards, correct?

Lefty

hi.. sorry for late replay. I didnt even get notification. (just happen to be checking up on thead) :)

1.) for your first question.. passing through both caps... I believe that it is. **(but I dont think it should be a problem, as I have built two other identical boards, so far (3 in total)....and others dont have any problems)?.. however Im fairly inexperienced in all this still.

2.) I have both 5v+ and GND from the MAIN Arduino going to the GND and 5v+ of the custom board. (so yes, common GND) :)

theres not much that can be bridged.. unless its on the main chip somewhere?

(not sure where to start testing)..

DRT/RESET? before after caps/resistors?..etc

if I quickly short reset pin directly on chip.. to GND.. I see a quick red light flash...

if I shirt DTR & GND.. I get no red blink.. (is it even supposed to there?)

bump...

still have a board.. that wont take sketches.. but seemed to take the bootloader 'ok'. (Optiloader by the way)