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Topic: ATmega328P - reset not working (Read 4 times) previous topic - next topic

JimG

I have a new ATmega328P that won't respond to pulling the RESET pin low.  Other new MCU's installed in the same board (an Uno clone with clamping diode on the reset line) work fine, but this particular chip will not reset.

Tried:
1.  Resetting from Arduino IDE (DTR signal)
2.  Pressing the reset button on the board
3.  Using a wire to manually short the MCU reset pin to GND plane.
4.  Re-flashing the bootloader multiple times (avrisp)
5.  Installing the bad chip into other known-to-be-good boards.

AVRDUDE reports the fuse settings as (all seem OK to me):
lfuse 0xff
hfuse 0xde
efuse 0x05

Apparently the Uno bootloader is being successfully loaded because I get the expected 3 short LED flashes on powering up the board.  But nothing I've tried will allow the board to be reset once it is powered up

I hate to throw the chip away, but there seems to be something wrong with it.  Any suggestions beyond the things I've already tried?

Jim
TC4 Open Source Digital Thermometer and Temperature Controller
http://code.google.com/p/tc4-shield

Coding Badly

Quote
4.  Re-flashing the bootloader multiple times (avrisp)


Does that seem to work?

JimG

Yes, it does.  Which seems odd since a reset is required for this to happen, right?

Jim
TC4 Open Source Digital Thermometer and Temperature Controller
http://code.google.com/p/tc4-shield

Coding Badly


Yes.

When you wrote...

Quote
I have a new ATmega328P that won't respond to pulling the RESET pin low.


...what did you mean?  What are the symptoms?  What leads you to believe reset is not working?

JimG

Two things tell me that reset is not working:

1) Can't upload sketches
2) When the reset switch is closed (pressed), the bootloader does not flash the LED.

The bootloader does flash the LED upon power up, though, so I know that both the LED and bootloader are ok.

Jim
TC4 Open Source Digital Thermometer and Temperature Controller
http://code.google.com/p/tc4-shield

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