ATMega32u4 HWB Issue

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I'm trying to use the /HWB pin to run my bootloader on an ATMmega32u4. I compiled the basic LUFA DFU Bootloader, using 0x7000 as the BOOT_START value, 32KB flash size and 4K boot size. I have the HWBE fuse set. I have the /HWB line pulled high with a 10K resistor, and a button connecting it to GND when pressed.

When I plug it in via USB, it works fine, my computer finds it even when I don't press the button to enable the bootloader. When I power it externally through an ISP header, it also runs the bootloader. The button has no effect. What could be happening?

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Is the BOOTRST fuse also set? That will override all other settings and make the chip always run the bootloader on power-on.

- Dean :twisted:

Make Atmel Studio better with my free extensions. Open source and feedback welcome!

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I just reset the fuses such that HWBE is set and BOOTRST isn't. I have it plugged into my computer and whenever I press RST, regardless of the state of HWB it still runs the bootloader. Any idea what could be happening?

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Never mind, it just started working. I set he fuses a second time and it began to work (faulty chip I suppose?). Thanks for your help Dean!