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Topic: Debugging Atmega2560 barebones board (Read 157 times) previous topic - next topic

arduinoink

Hi all,
I designed a barebones board for the Atmega2560 (oscillator, caps, reset resistor, power supply) and am having trouble programming a bootloader onto it.

Pretty sure the problem is with the programmer but I wanted to also do as much testing as possible on the barebones board just in case.

So far I have made sure there is continuity between the ground and power lines, that all the decoupling capacitors are soldered correctly, the power supply is outputting correctly and the TMS/TMK pins are showing a high voltage.

The board is taking 20-30mA or so and upon shorting the reset to ground I get a dip in current draw.

I was wondering if there are any other tests that would work on a board/chip that has not been flashed/fuses changed?

Would a factory fresh Atmega2560 be utilizing the external crystal? Could I test the crystal with an oscilloscope or would it only oscillate once the fuses are changed? If it is using an internal oscillator from the factory, could I test to see if it was running or will the chip be in a passive state fresh from the factory?

Any advice would be greatly appreciated.

WattsThat

The default factory fuse settings use the 8 MHz internal clock. The simplest way to test is a blink sketch.

If you cannot install a bootloader, it's probably a hardware issue.
Vacuum tube guy in a solid state world

srnet

Pretty sure the problem is with the programmer but I wanted to also do as much testing as possible on the barebones board just in case.
So check the programmer on a known good and working board an Arduino Pro Mini for instance.
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