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Topic: Software reset doesn't work on my Diecimila compatible board (Read 1 time) previous topic - next topic

hhpp

Hi,

I haved designed a board compatible with Diecimila(ATmega168). I do connect DTR pin of FTDI chip to reset pin of ATmega168. However I found that I still need to press the reset button after clicking upload icon in arduino environment.

My question is: how to upload the firmware without pressing reset button?

Thanks for any comments or suggestions.

HHPP

johnwasser

You could check the Diecimilla schematics and see where your circuit differs from theirs.

http://arduino.cc/en/uploads/Main/Arduino-Diecimila-schematic.pdf

The schematic shows both DTR# and RTS# from the FTDI FT232RL chip being connected to the Reset line through resistors marked "100_NM" (whatever that means).
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retrolefty

Quote
resistors marked "100_NM" (whatever that means).


The "NM" means not mounted, as in not installed in production units.


Lefty


retrolefty


Hi,

I haved designed a board compatible with Diecimila(ATmega168). I do connect DTR pin of FTDI chip to reset pin of ATmega168. However I found that I still need to press the reset button after clicking upload icon in arduino environment.

My question is: how to upload the firmware without pressing reset button?

Thanks for any comments or suggestions.

HHPP


Many other designs also use the simple .1ufd series cap between FTDI DTR/ pin and the AVR reset pin successfully. Can you post a drawing of your design to see what might be preventing auto-reset function from working?

Lefty

hhpp

I have attached my schematic capture.
Please let me know if you find anything wrong. Thank you Guys!

retrolefty


I have attached my schematic capture.
Please let me know if you find anything wrong. Thank you Guys!


Try it without C-29. And if R-16 isn't just a piece of wire, replace it with a piece of wire.

Lefty


hhpp

Hi Lefty,

Thank you very much for your suggestion. I removed C29 and it works!!

Regards,
hhpp

madworm

• Upload doesn't work? Do a loop-back test.
• There's absolutely NO excuse for not having an ISP!
• Your AVR needs a brain surgery? Use the online FUSE calculator.
My projects: RGB LED matrix, RGB LED ring, various ATtiny gadgets...
• Microsoft is not the answer. It is the question, and the answer is NO!

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