Arduino Forum

Using Arduino => Microcontrollers => Topic started by: 0miker0 on Apr 30, 2013, 04:55 pm

Title: Atmega32u4 reset line on custom board
Post by: 0miker0 on Apr 30, 2013, 04:55 pm
I've created a custom board using the 32u4 programmed with the Leonardo bootloader via the USBtinyISP and for some reason it will not reset on power up. I have a 10K pullup on the reset line but no 0.1uF cap to ground like on the 328P designs. Every 32u4 schematic I've seen has just a 10K pullup and a reset button to ground so I copied this layout.
I power up my board and nothing until I hit the reset button. Then it starts up properly. I'm guessing that a real Arduino Leonardo board probably resets properly on power up without hitting the reset button.

Thanks,
Mike
Title: Re: Atmega32u4 reset line on custom board
Post by: cmiyc on Apr 30, 2013, 09:21 pm
What's the power source?  Your power source could be causing the chip to brown out on power up, disabling itself until reset.