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Topic: Connections for bootloading a nano based board (Read 571 times) previous topic - next topic

Lsnyman

I am laying out a pcb based on a Arduino Nano, so it has SMT Atmega328 and the FT323RL. I am a little confused as to what connections I need for bootloading the chips as they will be blank obviously.
Can they be bootloaded through the USB port or do I Have to have access to MOSI, MISO and SCK just for bootloading?

CrossRoads

Need SCK, MISO, MOSI, Reset, Power, Gnd for bootloading. Not USB port.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Dr_Ugi

Obviously, all of those pins except for reset are used for other functions so you would most likely have access to them anyway.  It's convenient that they are brought together in the six-pin connector but it's not essential.  You just need some sort of header on each of those pins that you can connect to.  Reset also.

If you are laying out a PCB with permanent connections to some pins, bear in mind that low-impedance loads on the pins for MISO, MOSI, or SCK can prevent communication through these pins for burning the bootloader.

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