Atmega32u4-au boot loading problem

Projects Programming
1

Hello,

I'm trying to boatload to a new off the shelf Atmega32u4. I'm using a Arduino as ISP with a custom board for the m32u4.

When I try to uploading the boot loader I get the following message:

avrdude: Device signature = 0x3c0102
avrdude: Expected signature for ATmega32U4 is 1E 95 87

If I try to do the boot load again the Device signature changes to something else.

The custom board has a 8MHz resonator

Does any one have any ideas.
Checked list
ISP wiring
correct device selected in the IDE for the boot load.
Clock

2

Post a link to the place you got the ArduinoISP code from. There are several different versions on the Internet with different functionality.

Which boot loader do you try to upload? That of an Arduino Leonardo? That doesn't work because the Leonardo runs at 16MHz. Which board did you select in the IDE?

3

Hi Pylon,

Thanks for the reply, I thought I was going to just get tumbleweed. Answering your questions
The Arduino ISP sketch used is r1.6.12 Randall Bohn,
The boot loader I used was based on the Lillypad USB Boards.txt file.

In the mean time I have managed to get it working. I wanted to cut board space so I left out the 5v and GND on the ISP header, with the custom board been 3.3v, the power supply on these pins needed to go through an LDO Regulator anyway so I thought I could just use my external power supply........ and No, you can't.

I had to connect the 5v and gnd from the arduino I was using as the ISP, my guess something to do with reset. but honestly I still don't really understand why this is the case.

4

The Arduino ISP sketch used is r1.6.12 Randall Bohn,

Link not description!

In the mean time I have managed to get it working. I wanted to cut board space so I left out the 5v and GND on the ISP header, with the custom board been 3.3v, the power supply on these pins needed to go through an LDO Regulator anyway so I thought I could just use my external power supply........ and No, you can't.

Without having a common ground it's clear that it cannot work. The voltage levels have no reference so they may be anywhere.

BTW, you may damage your custom board if the VCC is 3V3 and the voltage level on the SPI pins is the 5V from the Arduino used as ISP. Use a level converter in-between them.