Hi,
i am newbie in arduino, i would like to ask you, how much time arduino nano want for start, load program and do first instruction.
(I would like to start arduino only by short 12V impuls (to vcc) and first instruction is switch relay (12v) to vcc)
thx for reply, mcshort
The bootloader of the Arduino waits some time, like a few seconds or so.
The microcontroller in the Arduino is a Atmel AVR chip, the ATmega328P. If you would use that chip without bootloader, it is withing a millisecond.
Can't you use the 12V pulse directly for the Relay?
Can you keep power to the Arduino, and let the Arduino wait for the 12V pulse ?
yep, i would like to you arduino nano with this chip, this board is with bootloader...
i not want to keep arduino on power all time (power consumption), i would like to start it with pulse, swith relay for power to arduino, after some cycles power off "supply relay" -> power off arduino
You should probably sleep the arduino rather than use a relay -- Sleeping can bring the current down to one microamp or less, and a relay needs quite a bit more than that to stay on.
The datasheet will tell you all you need to know about start up times from sleep modes: http://www.atmel.com/Images/doc8271.pdf
However, it can't tell you about how long it takes to initially start up because the bootloader has to run, which was made by arduino. If you take the bootloader off the datasheet can give you the time, though.
thank you, but if i would be use sleep mode, boot time will be longer almost same.
I read some topic about "my problem", and if i use external usb isp programer, i think i can burn out the boot loader, no lag during start i hope.
Yes, if you upload the sketch via ICSP the sketch will run straight away.